truecrypt question

[Bart Silverstrim]

I'm hoping there's some truecrypt users out there...

I created a file, file.tc, using the options:
normal
no filesystem
serpent-twofish-aes hash
no keyfile
mouse data for entropy

A 70 gig file was created.

I mounted it with
sudo truecrypt ./file.tc

Then I checked it.
sudo truecrypt -vl

Which told me the file was mounted as /dev/mapper/truecrypt0

I then ran:
sudo mkfs.ext3 /dev/mapper/truecrypt0

The system locked up when it was almost halfway through!  Completely 
locked up, had to reboot.

I tried it again, this time with graphic effects turned off since I'm 
running the binary NVIDIA drivers on a fairly recent card that isn't 
supported natively under Ubuntu and thought it was an X quirk.

Locked up again, with the same steps (to format, since the file is 
already created).

Anyone else have this sort of thing happen to them?

-Bart