If you got this problem (or something like it) while updating packages with urpmi.update -a or urpmi --auto-updates :
/bin/mv: cannot stat `/var/cache/urpmi/partial/descriptions': No such file or directory
Can't move file /var/cache/urpmi/partial/descriptions to /var/lib/urpmi/Main Updates (Cooker2011.0-2)/descriptions
Then the solution is by removing the file /var/cache/urpmi/mirrors.cache for urpmi to use different mirror. This is because the mirror has problem. So issuing this command should solve the problem:
rm -fv /var/cache/urpmi/mirrors.cache
That's all there is to it. Have fun!