mail app gone all screwey

In jaguar my mail app has started acting weird. It wont use the sound to notify me of new mail when I receive it. Then after I'll have noticed new mail (usually by cmd-tabbing) I will get the sound maybe 10-15 minutes later. but only sometimes.

Now...I dont know if repairing permissions will fix this, but I'll try that. Has this happened to anyone? DO I have to re-install mail?? that would not be fun...having to re-download all those messages....


thanks