Focusing on the configuration aspect of this thread and not the crash you experienced:
You really should just re-install to get back to a base configuration... as you incrementally make changes, backup your Opus config so that you have a config to go back to in case you goof something up again. At a glance, I suspect you blew away some of the default Events (such as the Drag-and-drop event) on the All files and folders item in the File Type editor. Don't do that 
... But in any case, you should make frequent backups as you continue to tweak your config, and when you're finally happy with your changes, do a last backup and store it someplace safe in case you need to revert back to a known stable config.