theme my login error log

Hello

I have added shortcodes for login and registration on the same page. When I try to register a new user, the following message appears

Fatal error: Call to a member function get_option() on a non-object in /var/sites/g/gentlemovement.co.uk/public_html/wp-content/plugins/theme-my-login/modules/custom-redirection/custom-redirection.php on line 93

Am I using the plugin incorrectly? The wpmu membership plugin is also active and should be compatible.

Txs