Network Applications Running Slow

I have Novell Netware 6.5 as a server and Windows XP pro and home clients. The XPs are running Novell client for windows XP 4.83 SP2 and 4.90 SP2. Eversince i have installed Novell 6.5 my network applications like creative solutions and Profx system(a tax program) has been running extremely slow. After since i installed Nortron Antivirus on client computers the programs have gone drastically slow. I tried to disable the Antivirus software but there was not a significant change in speed. Anyone know why the network applications are running slow and the local applications are running normal?