Thank you for your post.
Create a second user account on the MacBook Air, and log in to that second user account. Launch Bento. Does this work?
If so, then there is something in the first user account that Bento does not like. Run Disk Utility and repair disk permissions.
If this doesn't work, then uninstall and reinstall Bento and try again. If this still fails, then there is something in your OS that is stopping Bento from loading.
Any other information you can provide may help in narrowing down the possible causes.
Since this is the FileMaker Pro/Server forum, in the future, please post your question to the Bento forum at forums.filemaker.com.