Warning: Unknown config option in "/etc/munin/plugin-conf.d/munin-node" under "[vebc*]": env.config at /usr/sbin/munin-run line 619, <IN> line 19.
[...]
Use of uninitialized value in concatenation (.) or string at /usr/sbin/munin-run line 321.
ERROR: Could not execute plugin (plugin doesn't exist?).

 less -N `which munin-run`
[...]
    619             warn "Warning: Unknown config option in \"$dir/$file\" under \"[$service]\": $_";[...]

# env.config

[...]
Use of uninitialized value in concatenation (.) or string at /usr/sbin/munin-run line 321.
ERROR: Could not execute plugin (plugin doesn't exist?).

 less -N `which munin-run`
[...]
    321         next unless ($file =~ /^$ARGV[0]$/);

# telnet localhost  4949
Trying 127.0.0.1...
Connected to pv10.ncsrv.de.
Escape character is '^]'.
# munin node at pv10.ncsrv.de
fetch vebc_numfile_privvmpages_lockedpages_001
.
config  vebc_numfile_privvmpages_lockedpages_001
# Unknown service
.
Connection closed by foreign host.

$ /usr/share/munin/munin-update --debug --nofork --stdout --host foo.example.com --service vebc_numfile_privvmpages_lockedpages_001
Nov 03 17:38:43 - [22244] Starting munin-update
Nov 03 17:38:43 - [22244] Processing domain: localdomain
Skipping host "localhost.localdomain" - not in hostlist
Nov 03 17:38:43 - [22244] Processed domain: localdomain (0.00 sec)
Nov 03 17:38:43 - [22244] Munin-update finished (0.09 sec)

$ /usr/sbin/munin-run  vebc_numfile_privvmpages_lockedpages_001 config
Warning: Unknown config option in "/etc/munin/plugin-conf.d/munin-node" under "[apache_accesses]": env.autoconf at /usr/sbin/munin-run line 619, <IN> line 12.
graph_title beancounter for VE001: numfile privvmpages lockedpages
graph_category VE001
graph_info 'VE bean counters info'