Retrospect problem with PowerBook 3400?

Michael Wise writes: "I have found a conflict with Retrospect 4.0 and the Apple PB 3400. When backing up 3400's over TCP/IP, the Retrospect server's connection to a 3400 frequently fails with a 'error 519 network communication failed' message. We have duplicated this on all of our 3400's running 7.6.1 and OT 1.1.2. I have not yet been able to duplicate the problem on a 3400 running 7.6.1 and OT 1.3b2. Dantz says they are aware of the problem and suggest backing up 3400's over AppleTalk until their engineers can isolate and fix the problem."