Check Memory returning Unknown HZ value



I wonder if anyone can help with this? I have a fully working Nagios installation monitoring many servers. One of them is returning an error before the memory figure:

[blockquote][[email protected] libexec]# ./check_memory 20% 10%
Unknown HZ value! (194) Assume 100.
Status: OK - 86% memory free.

I have no idea what to try with this one.