XMON causing Outlook syncronization to fail

We have NOD32 for Exchange (Exchange 5.5 on WinNT4sp6) and have been having problems with Outlook syncronization failing. We have narrowed it down to XMON causing the problems and have had to temporarily turn off XMON to let users sync there email. It seems to be that NOD32 delays things enough that things fail. Looking at the sparse documentation for XMON I thought it might be the "Time Limit" under the performance settings that would block an email message and cause things to fail. But then I read:

Time Limit (for Exchange 5.5) - sets the time interval for running the virus scanner.
Time Limit (for Exchange 2000 and 2003) - a time limit for scanning an individual file.

What in the world does "sets the time interval for running the virus scanner" mean? If it needs more time I would think that I might set it higher, but if it is how often it runs, I might want it lower. Please clarify the issue.

Any thoughts that might help salve the issue? Thanks!

Steve McCracken