(context post by knightmb)
You are using Windows I can tell, but what version, arch (32 or 64 bit) ,etc?
http://bitcointalk.org/index.php?topic=316.0
Maybe that thread helps.
More directly, this: topic 246
I will be posting release candidate of 0.3.1 with this fix shortly. Please try that and let me know if it fixes the problem.