Exchange 5.5 & GroupShield 4.5

We have GS 4.5 install on a Exchange 5.5. with SP3 loaded. Every couple of months our GS starts to fail on us. Right we are getting an error in our Event Log 1066. The says ( Network Associates GS On-Access Dll Unloaded. This happens every 10 secounds. Also when I look into the version tab its comes up with zeros.
Its seems every couple of months we starting haveing problems with this product and we have to do uninstall then a reninstall. Does anyone else have these type of problems with GS.