Are you sure the tensioner wheel is aligned with the chain path? Every tensioner bracket, almost without exception requires a slight twist to get the wheel in alignment with the chain. As for the wheel not turning this could be due to misalignment or chain tension. A too loose or a too tight chain would account for the wheel not spinning as designed. There is a thread > http://motorbicycling.com/f11/chain-...ons-11815.html
That has a lot of good information on the tensioner including options for using or not using one. Read up on what others have done to get past the tensioner hurdle.