Did you number the additional new Maps sequentially starting with the number after the last one in the folder already.

Example:

MB3D comes with 15 Maps preloaded adding Maps after that the Maps should be labeled 16, 17, 18....etc.

Only consecutive numbers for Map names will work. If you still can't access them Click INI tab and make sure the Ini Dir is set up to look for maps in the correct Folder where the Maps are located.

Remember...No matter where you go there you are