I'm having exactly the same problem. Have lost login availability after moving the blog structure up one directory to root (following instructions found in thse pages). The "Retrieve password" function even sends me 2 emails with different password strings. Uploading the 1.2 wp-login file does nothing for me. The emails states UTF-8 encoding although my blog is set to ISO-8859-1. No idea if this can cause trouble. Have tried changing the password and then creating a new user directly in PHPMyAdmin but to no avail.