XF 1.2 [Solved]Enabled debug mode, lots of stuff broke.

[WaddleJrJr]

Here's what happened. I enabled debug mode like I have in the past to do something, however this time when I did I received several errors, relating to an addon that I don't really need anyways. They are as follows...

Server Error
Declaration of Waindigo_LoginAsUser_Extend_XenForo_Model_User::updateSessionActivity() should be compatible with that of XenForo_Model_User::updateSessionActivity()

1. XenForo_Application::handlePhpError() in XenForo/Autoloader.php at line 119
2. XenForo_Autoloader::autoload() in XenForo/Autoloader.php at line 119
3. XenForo_Autoloader->autoload() in XenForo/Application.php at line 1000
4. XenForo_Application::autoload() in XenForo/Application.php at line 514
5. XenForo_Application::resolveDynamicClass() in XenForo/Model.php at line 189
6. XenForo_Model::create() in XenForo/Visitor.php at line 403
7. XenForo_Visitor::setup() in XenForo/Session.php at line 366
8. XenForo_Session::startAdminSession() in XenForo/ControllerAdmin/Abstract.php at line 48
9. XenForo_ControllerAdmin_Abstract->_setupSession() in XenForo/Controller.php at line 304
10. XenForo_Controller->preDispatch() in XenForo/FrontController.php at line 336
11. XenForo_FrontController->dispatch() in XenForo/FrontController.php at line 134
12. XenForo_FrontController->run() in /home/brajoc/public_html/admin.php at line 13

However, I was not able to get back in to disable debug mode. And now when I go to view my site at all I get this error -
Fatal error: Call to undefined method XenForo_Model_User::canLoginAsUsers() in /home/brajoc/public_html/library/Waindigo/LoginAsUser/Listener/TemplateHook.php on line 36

Is there any way I can fix this? I don't have a recent backup to revert to, because this error was totally out of the blue. The only other thing I thought of is deleting the files relating to that mod, however that wouldn't really do all the changes that uninstalling would do, so would that really work?

Thanks for any help.

UPDATE - I tried it without the folder for the addon and got a 502 Bad Gateway error from both the normal site and the admin control panel.

UPDATE AGAIN - I have fixed the problem by going into the code file for the addon's model user, and taking the function in question and replacing it with Xenforo 1.2's version of it.