Blank screen after submitting password reset request

Pretty much as the title says. Once I follow the reset link in the email, fill out my new password, and submit, I'm just taken to completely blank page. When I turn on WP_DEBUG, here's what I get:
Fatal error: Call to a member function get_error_data() on a non-object in /nas/wp/www/staging/msfirstchart/wp-content/mu-plugins/force-strong-passwords/slt-force-strong-passwords.php on line 103

I'd be happy to send along our test account credentials, but I'm not sure what the best way to securely do so is.

Also of note is that the problem still occurs with all other plugins deactivated.