Hi Tim.
I can't rely help you but I can tell you what I found out in my PDA application.
I got error 55 when init serial port. This error tells me that a network connection is active.
The reason for that was a active debug interface on my Win CE target.
In your case it could be some other process like active sync or so that might block
your serial device. Have a look ar that first.
With kind regards
Martin Kunze
KDI Digital Instrumentation.com
e-mail: martin.kunze@digital-instrumentation.com
Tel: +49 (0)441 9490852