Exceeded mail quota on sent folder

[tegan]

When I open up squirrelmail or any e-mail client I get a strange error message. After typing an e-mail message and clicking the send button I get the following error...

ERROR: Could not append message to INBOX.Sent.Server responded: [ALERT] You exceeded your mail quota.Solution: Remove unneccessary messages from your folder and start with your Trash folder.

Now what makes this strange is that the mail is still being sent to the recipient. However the message can't be copied to the Sent folder for some quota reason.

I have the quotas set at 20mb. I have been doing a little research and came across a qmail quota patch (qmail-maildir++.patch). Any ideas on whether this is a patchable issue?

If I delete the e-mail account having problems with the sent folder quota and re-add it I don't get the error message, however It will magically reappear after sometime.

Any or all help appreciated.
-Tegan Snyder