You can delete your application files, and reinstall Animator.
Application files can be found here
OS X: Users/<username>/Library/Application Support/Sencha, Inc./Sencha Animator/
Windows XP: C:\Documents and Settings\<username>\Local Settings\Application Data\Sencha, Inc\Sencha Animator\
Windows Vista/7: C:\Users\<username>\AppData\Local\Sencha, Inc\Sencha Animator\
Linux: ~/.local/share/data/Sencha, Inc./Sencha Animator/ yourUserFolder/Library/Application Support/Sencha, Inc./Sencha Animator/
You will loose any preferences and templates you have set.