You have the correct belt. Getting a shorter one will have you driving all the time. We're missing something. Are you sure your belt is in the blade adapter pulley and all the way up the crankshaft, with the belt level with the belt guide. Second, I have had adapters where the built-in key has been sheared, causing not drive. If you turn the tranny pulley by hand, do the wheels turn? I know these are stupid questions, but this problem should be a simple fix. Wish I was stand there looking at the unit, should be able to diagnosis in 5 minutes.