The latest MouseHunt AutoBot script (version 2.04) only work on the new layout of MouseHunt. If you are running on old layout, the script will hang after sounding the horn. I will fix them in future, but currently the only way to make sure the script run without problem is use the new layout. Here is how you can do it:
First, go to Help > User Preferences
Tick New FreshCoat Layout and remember to click Submit button at the bottom.
Sorry, you all will forced to use the new layout for now.