I'm a fan of Norton Commander myself(imagine Norton software that works. Peter was still in charge those days...) -- and a little sad that the Linux ones aren't quite up to the standards of the NC tradition. Midnight Commander's cramped and unstable, xnc's bloated beyond recognition, and now yours is doing this... I might try and make my own some day.
First off, I'd check if you had the most
recent version of tux commander, if it's that old a program ubuntu may have grown lax in keeping it updated. [edit] It seems you do. Maybe try DOWNgrading it, that may help if the bug is recent. If that doesn't help, I'd run it with strace, which will generate copious output on stderr on what system calls are happening and which system call its freezing on.