Not sure if anyone else has had this problem, but I was a little frustrated when I couldn't get modprobe to work on my brand new 770, even though it was installed. The following commands managed to fix the problem.

(Note: You need to be root to do this.)

Obviously, this is much nicer than running insmod. Also, it's meant that I've been able to mount the ext3 partitions on my MMC as ext3 without having to faff around finding out what the missing dependencies are for ext3.ko.

Hope this helps someone.

Alex