Mail error message

Hi. I'm getting an error message:

The message “” could not be moved to the mailbox “Trash — On My Mac”

The destination mailbox “Trash — On My Mac” does not allow messages to be moved to it.

If I log in to MobileMe and delete the messages there it works OK. Mail has been acting a little kooky just lately and I've had to Force Quit a few times. Can anyone help? Thanks.

PS: yes, I did search if this has come up before but couldn't find anything.

How long has this been going on?

Just the last few days.

Here's a screen shot.

I'm guessing you already selected Rebuild from Mailbox in the tool bar. Under Accounts in Preferences do you have excess accounts that you don't use or that may conflict via services?

Yes, I tried that, and also repair permissions. Oddly, if I right-click on the message and select Move To... / My .Mac Account / Deleted Messages, it works.

I think I've fixed it. In the Mail approaching, select the Deleted Items folder under My .Mac Account, then from the menubar select Mailbox, Use this mailbox for… , Trash.