I've been following the Bootable USB Thumb Drive with “Full” Disk Encryption how-to to install Backtrack 4 on my Asus eeepc 900 and had no problem creating a working USB thumb drive. I repeated the procedure to install it (and encrypt it) on my SSD but Ubiquity crash when I reach step 4. I can see the partitioning screen for a second and it just crash.

Code:
bt ubiquity[8039]: Device /dev/sdb1 not found in os-prober output
bt ubiquity[8039]: Switched to page stepPartAuto
bt ubiquity[8039]: Exception in GTK frontend (invoking crash handler) :
bt ubiquity[8039]: Traceback (most recent call last):
bt ubiquity[8039]:      File "/usr/lib/ubiquity/ubiquity/segmented_bar.py", line 500, in do_expose_event
bt ubiquity[8039]:          cr.paint()
bt ubiquity[8039]: MemoryError
bt ubiquity[8039]:
bt ubiquity: /lib/partman/lib/base.sh: line 146:
/lib/partman/automatically_partition//do_option: no such file or directory
I since tried without encryption (simply running the install.sh script) and I encounter the same problem.

Any idea on what to try next??