Mail App issues

[macbookairman]

I updated to the new version of leopard today (10.5.4). Suddenly my mail rss feeds won't update, i have restarted mail, and they still won't work. However, I don't think the update messed it up. I think I might have messed it up somehow by looking through the "package contents" and various files in that.

So If I were to delete mail, and recover a version from...say....a week ago or so (using time machine), what sort of things would I have to do? Would mail have to be reconfigured (ex: re-adding my accounts and rss feeds)?

thanks