I just finished the Modifying Page Layouts module and when I tried to check the challenge, I received the error below.  Any suggestions?

Challenge not yet complete... here's what's wrong: 
There was an unexpected error while verifying this challenge. Usually this is due to some pre-existing configuration or code in the challenge Org. We recommend using a new Developer Edition (DE) to check this challenge. If you're using a new DE and seeing this error, please post to the developer forums and reference error id: GYYHRFTM