Exceptions/exclusions on NAV2006

I'm running Win2K and NAV2006.  Every time I start an application such as Word or Excel, NAV appears to run a scan on it, so it can take 2 minutes to open either app.  When I load an actual file to edit, NAV scans this as well, taking another couple of minutes.  Clearly this is stupid, but I cannot for the life of me find any way to exclude Word and Excel from these pointless startup scans.

Can anyone tell me how to set up exclusions in NAV2006?

Cheers, Roger