Can’t edit posts in 2.1.2!

This *just* started happening…I need to edit one of my posts, but instead I am shown the root of my blog with “Nothing found for Wp-admin Post Php?action=edit&post=297” as the title. It’s clearly trying to apply mod_rewrite rules to my admin directory (although I can get to every other page in the admin panel just fine). I’ve put an .htaccess file inside /wp-admin with:

<IfModule mod_rewrite.c>
RewriteEngine off
</IfModule>

In an attempt to prevent whatever it’s trying to do, but it doesn’t work. Yes, I know my WP version is old and I’m working on migrating my stuff to 2.5 but I need this to work *right now*! I did not change *any* settings before this started happening…as far as I can tell, it started without my doing anything. Any suggestions?