Well, no that's not a crash. That's the program not continuing because it doesn't have the resources it needs.

What possessed you to run --rebuild-tree when the problem was not a filesystem error but simply a lack of free space?

At the moment the only way out that I can see is to take an image of the partition (which you apparently already did), reformat the partition, and then recover your files from the image using loopback mount, something like this:

mount -o loop,ro -t reiser /data/part.img /mnt/oldhome

Hopefully you can get your files off it.