Hello Michael,
Obviously there is a problem, because you absolutely need the USB interface for using CATrain 2.x. Contrarily to CATrain 1.x, where the PC was doing all the job, this is the processor on the USB interface board which controls the modules and collects the feed-back information. Windows XP is too busy with its own complexity to care about user applications which require response time under 10 ms...
BUT, for experimenting CATrain and your two modules, you can still use CATrain 1.82, preferably on a PC running a 16 bit version of Windows (Windows 98, Windows Millennium).
After experimenting, if you consider using CATrain for controlling a larger layout, you can buy a processor and eventually a printed board to build the USB interface.
Kind regards,
Joël