Mounting images from drive problem

I’ve just bought a brand new BenQ 1640 drive and I’m already experiencing troubles.
I tried to write multiple CD images (.ISO format) onto one DVD-R disc (Verbatim MCC 002 and 004). I then opened the drive in explorer and could easily access all files (and open some .DOC and .XLS files that were also on the disc). But when trying to load the .ISO images as a virtual drive (tried both Alcohol 120% and DTools) the pc hangs, every time. I have to (hard) reboot and NOT open My Computer before unmounting all drives or it hangs again.

Since the data files are written fine, I guess this might be a driver conflict. Could anyone help me out here? I tried changing my drive from slave to master but that doesnt help. Or should I burn the ISO images in another format?
Any help is welcome!