It sounds like a video issue. I installed WinXP Pro without any problem on both version 5 and 6. Meanwhile, the latest version for VPC 5 is 5.0.4. It took me around 5hrs to complete the installation on my iMac 500 (upgraded Rev. A, OS X 10.1.x, v5.0.4), but it screamed on my DP 1.25.. took just less than 30mins.
Haven't tried it on OS 9.2