The PM quota(limit) for registered users is 50 messages.
.NET Supporters get 150 total.
The problem is, that when we imported PM's from the old site everyone's sent PM's filled up their quota like crazy. Some of you may want to keep more recent ones, but personally I had PM's in there that were 2+ years old. Alot of you will probably discover the same.
We could have just wiped these, but we wanted to give you all a chance to go through them yourselves.
If your total PM's from your both your Inbox, Sent Items or Stored Items is higher than this total you are probably experiencing problems with your PM's. To resolve most issues please delete older messages from your PM folders.
Once you get back within your quota limit, PM's should work properly. The PM info box in the site header should then also display the correct info.