This is the message i get on nagios for the localhost dns check routine:
Plugin timed out while executing system call
Its weird since the plugin has been working for the last months without any problem....
System is debian
i just tried updating/upgrading my debian and it still works as expected... try running it as user root and as user nagios from comman dline and see if there's some more info.
But this same plugin, in this same server works when it performs a dns check to another dns server we have....
If i run the plugin from the console, it seems to work perfectly....
are you sure there's no typo in the command defintion? are you using a different option somehow?