As explained in someone else’s blog, there is a bug in WP1.21 that allows the site URL to be corrupted in the database, and then the formatting on your site goes poof. The fix is simple.
If you simply comment out two lines in wp-login.php, the bug is prevented.// If someone has moved WordPress let’s try to detect it^M//if ( dirname(‘http://’ . $_SERVER[‘HTTP_HOST’] . $_SERVER[‘REQUEST_URI’]) != get_settings(‘siteurl’) )^M// update_option(‘siteurl’, dirname(‘http://’ . $_SERVER[‘HTTP_HOST’] . $_SERVER[‘REQUEST_URI’]) );^M
Also, you might want to fix the wp-options siteurl entry in the database.