I am sure that one of the Nabble team will be along shortly.
I'm guessing that you failed to remove the embedding before changing your domain. This will leave you unable to access your Nabble forum to update the embedding code. Your post at:
http://support.nabble.com/Change-domain-from-Blogger-to-personalized-domain-td7585451.htmlprovides the information needed for Nabble to help.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.