Thanks Kirilll, this is the detailed information about the issue:

** After making changes suggested by Thorsten I got the following error:

/////////////////// VZMIGRATE OUTPUT START ///////////////////////
root@hostbw-253 ~]# vzmigrate -r no --online --keep-dst -v 10.0.10.251 111
OPT:-r
OPT:--online
OPT:--keep-dst
OPT:-v
OPT:10.0.10.251
Starting online migration of VE 111 on 10.0.10.251
OpenVZ is running...
    Loading /etc/vz/vz.conf and /etc/vz/conf/111.conf files
    Check IPs on destination node: 190.2.55.204 10.0.10.204
Preparing remote node
    Copying config file
111.conf                                      100%  882     0.9KB/s  00:00

Saved parameters for VE 111
/usr/sbin/vzmigrate: line 382: [: missing `]'
    Creating remote VE root dir
    Creating remote VE private dir
    VZ disk quota disabled -- skipping quota migration
Syncing private
Live migrating VE
    Suspending VE
Setting up checkpoint...
        suspend...
        get context...
Checkpointing completed succesfully
    Dumping VE
Setting up checkpoint...
        join context..
        dump...
Can not dump VE: Invalid argument
iptables-save exited with 255
Checkpointing failed
Error:  Failed to dump VE
Resuming...
Running: /usr/lib/vzctl/scripts/vps-net_add
        put context
/////////////////// VZMIGRATE OUTPUT END ///////////////////////

After this I tried changing the tmpve var inside vz.conf, just in case I
didn't have the proper user's rights in /tmp folder. Nothing changed, the
same errores came up.

Then, I tried an offline migration, and it did the migration but the VE
never started (because of networking not bein started). Actually there are
41 process running, but there is not networking configuration running.
The same happens if I just rsync the VE private area and ve.cofig file.
Exactly the same networking problem.

/////////////////////////  VZCTL START 111 /////////////////////////////

[root@ovz98 ~]# vzctl restart 111
Restarting VE
Stopping VE ...
VE was stopped
Running: /usr/lib/vzctl/scripts/vps-net_del
Running: /usr/sbin/vzquota stat 111 -f
VE is unmounted
Running: /usr/lib/vzctl/scripts/vps-stop
Starting VE ...
Mounting root: /vz/root/111 /vz/private/111
VE is mounted
Set iptables mask 0x000017bf
Set features mask 0000000000000000/0000000000000000
Adding IP address(es): 10.0.10.200
Running: /usr/lib/vzctl/scripts/vps-net_add
Running VE script: /etc/vz/dists/scripts/redhat-add_ip.sh
bash: line 61:  3793 Segmentation fault      /bin/sed -e
"s|^$name=.*|$name=\"$value\"|" <${file} >${file}.$$
 ERROR: Can't change file /etc/sysconfig/network
Setting CPU units: 41562
Configure meminfo: 145261
Set hostname: hostname.domain.com
Running VE script: /etc/vz/dists/scripts/redhat-set_hostname.sh
bash: line 61:  3810 Segmentation fault      /bin/sed -e
"s|^$name=.*|$name=\"$value\"|" <${file} >${file}.$$
 ERROR: Can't change file /etc/sysconfig/network
VE start in progress...

/////////////////////////  VZCTL START 111 END /////////////////////////////


////////////////// DMESG OUTPUT ////////////////////////

ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
NFORCE-MCP61: IDE controller at PCI slot 0000:00:06.0
NFORCE-MCP61: chipset revision 162
NFORCE-MCP61: not 100% native mode: will probe irqs later
NFORCE-MCP61: 0000:00:06.0 (rev a2) UDMA133 controller
    ide0: BM-DMA at 0xffa0-0xffa7, BIOS settings: hda:pio, hdb:pio
Probing IDE interface ide0...
Probing IDE interface ide0...
Probing IDE interface ide1...
ide-floppy driver 0.99.newide
usbcore: registered new driver hiddev
usbcore: registered new driver usbhid
drivers/usb/input/hid-core.c: v2.6:USB HID core driver
PNP: PS/2 Controller [PNP0303:PS2K] at 0x60,0x64 irq 1
PNP: PS/2 controller doesn't have AUX irq; using default 12
serio: i8042 KBD port at 0x60,0x64 irq 1
serio: i8042 AUX port at 0x60,0x64 irq 12
mice: PS/2 mouse device common for all mice
md: md driver 0.90.3 MAX_MD_DEVS=256, MD_SB_DISKS=27
md: bitmap version 4.39
TCP bic registered
Initializing IPsec netlink socket
NET: Registered protocol family 1
NET: Registered protocol family 17
powernow-k8: Found 1 AMD Athlon(tm) 64 X2 Dual Core Processor 5200+
processors (2 cpu cores) (version 2.10.00)
powernow-k8: MP systems not supported by PSB BIOS structure
powernow-k8: MP systems not supported by PSB BIOS structure
Using IPI Shortcut mode
Freeing unused kernel memory: (0073a000-00775000) 236k freed
Write protecting the kernel read-only data: 403k
Time: hpet clocksource has been installed.
USB Universal Host Controller Interface driver v3.0
ohci_hcd: 2005 April 22 USB 1.1 'Open' Host Controller (OHCI) Driver (PCI)
ACPI: PCI Interrupt Link [LUB0] enabled at IRQ 11
PCI: setting IRQ 11 as level-triggered
ACPI: PCI Interrupt 0000:00:02.0[A] -> Link [LUB0] -> GSI 11 (level, low) ->
IRQ 11
PCI: Setting latency timer of device 0000:00:02.0 to 64
ohci_hcd 0000:00:02.0: OHCI Host Controller
ohci_hcd 0000:00:02.0: new USB bus registered, assigned bus number 1
ohci_hcd 0000:00:02.0: irq 11, io mem 0xdfeff000
usb usb1: configuration #1 chosen from 1 choice
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 8 ports detected
ACPI: PCI Interrupt Link [LUB2] enabled at IRQ 10
PCI: setting IRQ 10 as level-triggered
ACPI: PCI Interrupt 0000:00:02.1[B] -> Link [LUB2] -> GSI 10 (level, low) ->
IRQ 10
PCI: Setting latency timer of device 0000:00:02.1 to 64
ehci_hcd 0000:00:02.1: EHCI Host Controller
ehci_hcd 0000:00:02.1: new USB bus registered, assigned bus number 2
ehci_hcd 0000:00:02.1: debug port 1
PCI: cache line size of 64 is not supported by device 0000:00:02.1
ehci_hcd 0000:00:02.1: irq 10, io mem 0xdfefec00
ehci_hcd 0000:00:02.1: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004
usb usb2: configuration #1 chosen from 1 choice
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 8 ports detected
SCSI subsystem initialized
libata version 2.21 loaded.
sata_nv 0000:00:08.0: version 3.4
ACPI: PCI Interrupt Link [LSA0] enabled at IRQ 15
PCI: setting IRQ 15 as level-triggered
ACPI: PCI Interrupt 0000:00:08.0[A] -> Link [LSA0] -> GSI 15 (level, low) ->
IRQ 15
PCI: Setting latency timer of device 0000:00:08.0 to 64
scsi0 : sata_nv
scsi1 : sata_nv
ata1: SATA max UDMA/133 cmd 0x0001d480 ctl 0x0001d402 bmdma 0x0001cc00 irq
15
ata2: SATA max UDMA/133 cmd 0x0001d080 ctl 0x0001d002 bmdma 0x0001cc08 irq
15
ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1.00: ATA-7: WDC WD2500KS-00MJB0, 02.01C03, max UDMA/133
ata1.00: 488397168 sectors, multi 16: LBA48
ata1.00: configured for UDMA/133
ata2: SATA link down (SStatus 0 SControl 300)
  Vendor: ATA       Model: WDC WD2500KS-00M  Rev: 02.0
  Type:   Direct-Access                      ANSI SCSI revision: 05
SCSI device sda: 488397168 512-byte hdwr sectors (250059 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
SCSI device sda: 488397168 512-byte hdwr sectors (250059 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
 sda: sda1 sda2 sda3 sda4 < sda5 >
sd 0:0:0:0: Attached scsi disk sda
kjournald starting.  Commit interval 5 seconds
EXT3-fs: mounted filesystem with ordered data mode.
EDAC MC: Ver: 2.0.1 Nov 30 2007
EDAC MC0: Giving out device to k8_edac Athlon64/Opteron: DEV 0000:00:18.2
input: PC Speaker as /class/input/input0
parport: PnPBIOS parport detected.
parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE]
8139cp: 10/100 PCI Ethernet driver v1.2 (Mar 22, 2004)
8139cp 0000:01:06.0: This (id 10ec:8139 rev 10) is not an 8139C+ compatible
chip
8139cp 0000:01:06.0: Try the "8139too" driver instead.
Floppy drive(s): fd0 is 1.44M
8139too Fast Ethernet driver 0.9.27
ACPI: PCI Interrupt Link [LNKA] enabled at IRQ 11
ACPI: PCI Interrupt 0000:01:06.0[A] -> Link [LNKA] -> GSI 11 (level, low) ->
IRQ 11
eth0: RealTek RTL8139 at 0xf8942c00, 00:08:54:b0:a5:98, IRQ 11
eth0:  Identified 8139 chip type 'RTL-8100B/8139D'
FDC 0 is a post-1991 82077
sd 0:0:0:0: Attached scsi generic sg0 type 0
ACPI: PCI Interrupt Link [LAZA] enabled at IRQ 11
ACPI: PCI Interrupt 0000:00:05.0[B] -> Link [LAZA] -> GSI 11 (level, low) ->
IRQ 11
PCI: Setting latency timer of device 0000:00:05.0 to 64
lp0: using parport0 (interrupt-driven).
lp0: console ready
ACPI: Power Button (FF) [PWRF]
ACPI: Power Button (CM) [PWRB]
ibm_acpi: ec object not found
md: Autodetecting RAID arrays.
md: autorun ...
md: ... autorun DONE.
device-mapper: ioctl: 4.11.0-ioctl (2006-09-14) initialised:
dm-devel@redhat.com
EXT3 FS on sda2, internal journal
kjournald starting.  Commit interval 5 seconds
EXT3 FS on sda1, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on sda5, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
Adding 4192956k swap on /dev/sda3.  Priority:-1 extents:1 across:4192956k
NET: Registered protocol family 10
IPv6 over IPv4 tunneling driver
process `sysctl' is using deprecated sysctl (syscall)
net.ipv6.neigh.lo.retrans_time; Use net.ipv6.neigh.lo.retrans_time_ms
instead.
eth1: link up, 10Mbps, half-duplex, lpa 0x0000
Bluetooth: Core ver 2.10
NET: Registered protocol family 31
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
Bluetooth: L2CAP ver 2.8
Bluetooth: L2CAP socket layer initialized
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM TTY layer initialized
Bluetooth: RFCOMM ver 1.8
Bluetooth: HIDP (Human Interface Emulation) ver 1.1
ip_tables: (C) 2000-2006 Netfilter Core Team
tun: Universal TUN/TAP device driver, 1.6
tun: (C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>
Netfilter messages via NETLINK v0.30.
ip_conntrack version 2.4 (8192 buckets, 65536 max) - 232 bytes per conntrack
VE: 106: started
eth1: no IPv6 routers present
VE: 108: started
VE: 112: started
VE: 113: started
VE: 114: started
VE: 115: started
VE: 500: started
VE: 900: started
VE: 901: star