I'm not even sure how solo mining works. Aren't you competing with all the pools for discovering the blocks? If so, wouldn't your chance of success, even with a 5GH/sec setup be very very small?
BTW, this is the suspected botnet: http://eligius.st/~artefact2/3/14j7N9wPPy2P2UPixzTgWJmMsUSGJAfM1Z
This account was not active until a few hours after a botnet was purged from btcguild. This guy sprung up from nowhere and is hashing at an almost identical rate.
I would notify the admin on this forum, but it appears that I am relegated to posting on the newb forum for a while.