inode ext2 error after apt-get upgrade Backtrack 5 R1

Hi all,
i have an usb installation of backtrack 5 R1 and it work fine. I made it with Linux Live Usb Creator.
My usb drive works well until i upgrade packages. Doing apt-get update && apt-get upgrade when i reboot i have a loop of inode error.
What can i do? It seems that's a problem with persistent file "casper-rw".
Thank you

You may have already solved this seeing as how it is almost three months old but for anyone else trying to figure this out:

1. Boot into another distro (other than the usb with problems)
2. Find the casper-rw file on your usb and run e2fsck on it

This solved my problems. I hope it helps you.