Platform: Windows XP Service Pack 2

I just upgraded from Novell Client 4.90 to Novell Client 4.91 SP2.

After installing the new client and rebooting, the Windows XP Security
Center reported that no anti-virus software could be found. I am running
the managed version of Symantec Antivirus 10. XP always detected the
software before; only after the upgrade could it not find SAV.

What happened? How do I fix this?

Thanks in advance.