Found the port settings in the registry, and added an entry for the com port I am using. Didn't help. The next thing I am going to try is to get some details of the communications protocol, and see if I can send stuff directly to the scanner through a terminal program, both from linux and then from wine. I should be able to figure out port settings that way, or whether this is going to work at all. I will post back here with results when available.
