In some rare circumstances the preferences file can get corrupted; this may be the problem.
Try trashing this file (you will need to reset your Comic Life preferences again).
1. Make sure you are not running Comic Life
2. Find the file ~/Library/Preferences/com.plasq.ComicLife3.plist
(In Finder, use the "Go to Folder" feature - select it from the Go menu with the Finder in focus, then type in the following in the window that appears: ~/Library/Preferences/ -- then look for "com.plasq.ComicLife3.plist" file)
3. Trash this file
4. Relaunch Comic Life