NT systems crashing simultanously

Today 07/24/2003 14:50 GMT we have had about 30 Win NT 4.0 and some Win2K machines bluescreening without us finding any cause for it. The only thing these machines have in common is that they are running Trend OfficeScan anti virus and are updated by Office Scan Remote Agent, but at different times in the night.

Has anyone had similar problems?