Warning: mysql_result() expects parameter 1 to be resource

I reset my user roles to default using the plugin “User Role Editor” and now my Event Scheduler / Calendar is not working properly. I’m getting the following error when I open any page with the calendar on it:

Warning: mysql_result() expects parameter 1 to be resource, boolean given in /home/vma7web/public_html/dev2/wp-content/plugins/event-calendar-scheduler/codebase/dhtmlxSchedulerConfigurator.php on line 95

<?xml version='1.0' encoding='utf-8' ?>

I tried to delete and re-install the Calendar, but when I reactivate it, I get this error:
The plugin generated 244 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.

And the Warning message still appears. Do I need to make an edit to line 95 in the code to make this work again?