I've been using the MkII on my Win2k systems for a long time, no problems. I just connected it to an XP Pro system (with Studio 4 already installed), let the system do its install thing when it saw the MkII, and then tried to connect from Studio - Connect Failed! Plugged it back into my Win2k system, all ok. Go to a second XP system (also with Studio installed), again I can't connect.
It's the same version of Studio on all machines (4.13 build 528). Is there something special about XP???