Annoying pop-up notice about "16 Bit Windows Sub-System", reading "C:\Program\Symantec\S32EVNT1.DLL"

Notice reads "An installable Virtual Device Driver failed Dll initialization. Chose "Close" to terminate the application. Followed by choices "Close" or "Ignore".

 

I'm posting here because of the reference to "Symantec", hoping Norton will tell me how to fix and get rid of it. Running Windows XP.

 

Thanks, DLRJMR2