CompuServe Messages

Help! I have an Emplant Deluxe, and want to use the Emplant's "A" serial port from the Amiga side. I have the latest Emplant software version 5.0, and am using empserial.device, unit 0, for that purpose. On AutoPilot and BackTalk, my US Robotics Sportster 14,400 Modem works fine for reading and writing messages, but simply will not download files. The CIS system sees way to many errors, and cuts the download short with a "Too many NAKs" message. However, if I use MacCIM to download the same files, using the same port, over the same modem, with exactly the same initiazation string, I can download with no problems at all! What's the problem? BTW the initiazation string I'm using is AT&F1&B1&D0&H1&I0. Any help would be appreciated, because I'd like to dedicate the Amiga's native serial port to my MIDI system. Also, using the same init string and the same modem from the native Amiga port using serial.device works just fine, as well. Ray Lewis ?|^)