I'm trying to track down the mail problem and was wondering if you could give me more information about it. Does it happen when you send mail while viewing another member's profile (meaning you sent it by clicking the "Send mail" link on the left side of the page? Or is it when using the "Send email" link in search results? Or is it just the main mail screen reached using the "mail" tab at the top of the site?
Also, can you tell me some of the browsers you are using?
Using Firefox, I can apparently send mail (because I'm getting replies to messages I send, aside from Chris'), but instead of reverting to the 'Message has been sent' screen, it automatically opens up a new blank message window.