hhmmm, ya i see the problem. I guess in the next version, I should have the delete button located on another page. That way when things screw up like this there is an easier fix.
I believe the problem comes from the single quotes used. The code you where given is really poor. They use single and double quotes. If you know how to edit the database, you can delete that entry. Next time you input the code, make sure to replace all single quotes with double.