RH8 groups going bad

I've had our web server crash for the third time in as many month 
yesterday.  Each time we seem to have lost all the group ID's which 
apparently creates all kinds of issues.  I managed yesterday to get the 
same thing twice just by installing all the updates to RH8.  Has anyone 
else had this problem?  Better yet can anyone tell me how to avoid it or 
fix it once it happens.

Larry