Very very old thread, I know, but after years of cursing (having to boot into Windows just for scanning) I switched from Parallels to VMWare Fusion, and OptiDriveControl finally works! In case someone else wants to scan using a Mac I thought I should superbump the thread.
I use VMWare Fusion and have the optical drives emulated as scsi-drives (they are in reality SATA drives though, but for unknown reasons I had to use SCSI to get them to scan).
Only issue is that I couldn't scan blurays in a virtual XP environment, so I switched to Windows 7.
(I never got qpxtools to work, maybe support for newer OSX is difficult)
I might try Virtualbox as well, when I have time, VMWare is a tad too expensive just for scanning.