DigiChat just got back to me:

The next time you're kicked out, try to do a tracert (right after you're kicked out). You can do this by opening a DOS window (Start->Programs->Accessories->Command
Prompt) and typing in:

tracert host5.digichat.com > tracert.txt

This will send the results to a file called tracert.txt. Send the resulting file to us at [email protected] and we'll pass it along to DC.

Thanks for working with us on this...