Transfer rate test in cdspeed - Vista 64 vs XP 32

[qanda]This thread is about the Pioneer DVR-215D. Click here to see full specs[/qanda]When I do a transfer rate test in cdspeed it works in xp but not in vista 64. The funny thing is that it works with +R but not with -R. I have a dualboot on my machine, so the hardware is the same in both operatingsystems.

Maxell -R, Verbatim -R and Traxdata +R. First the three on Vista 64, then the same on XP 32