We have a customized module in our sugar instance, and after upgrading from 6.2.1 to 6.3 we receive the following error

"There was an error processing your request, please try again at a later time"
Below that, the popup window states the following:
"if the error persists have the administrator disable ajax for this module"

I have attempted to both manually update the config_override.php and use the Admin Ajax settings panel to remove this from loading via ajax, the line is as follows
$sugar_config['addAjaxBannedModules']['0'] = 'OUR_CSTM_MODULE';
Adding this line now returns a HTTP 500 server error

I would like to be able to troubleshoot why ajax loader doesnt work with the said custom module, but at this point, im not able to access it at all, which has us in a bind