Had that exact setup for years now (CH combatstick gameport + Pro rudder), used it with win xp for 6 months without problems. I have never used the CH-drivers, because they caused problems when i first tried to install them in win2k. Was very difficult to clean those out of the registry, and they caused all kinds of problems.
I have always used the "6-button joystick with two POV's and throttle" setup, and made sure "Rudder" was hooked off. That setup has always been great - all buttons work, hardly ever had to recalibrate. Setup has been with me for at least 3 reinstalls of win2k and 2 reinstalls of XP - never had any of your problems.
My humble advice is: stay away from ch-drivers and delete all files and registry references to it. There is nothing to gain by installing them.
On a side note, my CH combatstick "died" recently after 5+ years of exceptional service. It was my own fault (thinkering inside), and i'm now waiting for my new CH usb-setup
