Did your downloaded ISO match the MD5 hash listed in the download area? Have you checked the hardware compatibility list here on the forums? Could be that you've got a non-compatible hardware device. Also, have you tried the 32-bit version of BT?
I'm no linux expert, but when I've seen these types of freezing issues (regardless of o/s), it's been the video card/chipset on the offending machine. Tweaking your BIOS settings (particularly the video ones) may help. You might also try downloading the new BT5r1.