I'm using scrobbler.py in my scroblog commandline scrobbler and I came across a small bug in the flush routine. It doesn't check to see if there are no records to flush, which would be true if there were a multiple of 5 records sent. I just added:
if len(SUBMIT_CACHE) == 0:
to the top of flush.
You can read more about scroblog here: http://linuxbraindump.org/2008/01/31/mp3-player-meet-lastfm