If you are logged into another MerchantCircle listing, you will not be able to create or claim a second listing. Logout of your current listing and try again.
Make sure you enter a DIFFERENT email since you can't use the same email for multiple listings.
Keep in mind you can only create one listing per hour (this prevents spamming of the network).
Unfortunately there isn't any way to merge multiple listing into one. But you can always add cities to a single listing to expand your business search results!