I'm having the following problem when I try to backup one of my VE's. I can run and it works fine.
[root@host ~]# vzdump --suspend 111
INFO: starting backup for VPS 111 (/vz/private/111)
INFO: starting first sync /vz/private/111 to /vz/dump/tmp27176
INFO: suspend vps
Setting up checkpoint...
Error: No checkpointing support, unable to open /proc/cpt: No such file or directory
ERROR: creating backup for VPS 111 failed (2.52 minutes): command '/usr/sbin/vzctl chkpnt 111 --suspend' failed with exit code 16 at /usr/bin/vzdump line 290.