This may not answer your question, but it may help others
I have successfully installed and used FlexColor on Vista Ultimate x64 using an Adaptec controller, for my Imacon Photo, which is just a smaller version then the Precision. I believe I have installed FlexColor 4.5, don;t have the machine here with me. I also had version 4 working on my Old XP box x32. Scsi Imacon's are slow, but still good! :-)
Cheers
Henrik