Win2k and PCAnywhere File Transfer Prob

We are running W2k Server with PCAw host running as a service. The host session runs fine until we pull up a File Transfer window. Response on the host then stops for a minute or so, then the file transfer window appears and when we start the transfer it completes at normal speed without problems. I have been to the Symantec KB and tried all the solutions there without success. The video card in the box is an ATI Rage series, but Symantec swears that should not affect things.
We need to get this system responding as it should.