'SIMBL (Smart InputManager Bundle Loader) allows you to build hacks for Cocoa applications and apply the code selectively based on an application's unique identifier. It's not really all that smart, or even clever, but it's smarter than just blindly loading code into an application'. From:
SIMBL
So, did you recently install something like a plugin? If so you may need to quit the app with the plugin in order to get rid of this file.