There seems to have a lot of issues with Feedburner and WP feeds. I know there is a plugin, but there seems to be issues on Feedburner's side with not being able to read the temporary URL for the feed generated.
After several days of trying to figure this out, I've come up with something that has worked like a charm for me and some of my local blogger friends.
PLEASE NOTE: that this may or may not work for you, but I have experienced great success using this method, and my Feedburner statistics are working very well again.
I've compiled everything I did in a post on my blog, which you can find here.
I'm willing to try and help others to get this to work, but please understand that I am using WP 2.0 ONLY, and I use permalinks, and it's possible your original .htaccess file is different than mine. There are other issues as well, such as your host may have issues with you tinkering with .htaccess.
I hope this helps others that have been having problems.