I've got something similar and I've found:
http://lists.laptop.org/pipermail/bu...ne/078204.html

for me it's:
[ 89.520050] JFFS2 error: (337) read_direntry: illegal nsize in node at 0x71640f8: nsize 0x56, totlen 0x37e
[ 99.002563] JFFS2 notice: (337) check_node_data: wrong data CRC in data node at 0x0592e800: read 0x6d3b97ba, calculated 0x1ec4b25a.

Reflash didn't change a thing - I'll have to get used to this probably.

Edit: my n770 got kind of worse after next flash - it powers itself down with no startup after that. I have to remove battery for a while to be able to switch it on.