1.0: problems with archives. they’ve disppeared.

December has disappeared. Can someone help me fix this?
I am using the mod_rewrite htaccess stuff with these settings:
/archives/%year%/%monthnum%/%day%/%postname%/
I didn’t change them till the problem occured on the 28th I think it was, when I posted something after a week of not having done so. All of a sudden, the site only displayed that one post. I deleted the post, thinking maybe something had gone wrong, and the other’s disappeared. Now, there are only posts from January 2004.
Any help would be appreciated.