Oldschool Dinosaur Movie from the 80's

Does anybody remember a movie from the 80's (possibly very early 90's) where a boy is transported either back in time or to a parallel universe full of dinosaurs? Here's what little I remember of it :

• It definately wasn't a cartoon, I'm pretty sure the actors were all wearing costumes.
• The dinosaurs walked upright and spoke.
• IIRC there were good and bad dinosaurs. The good ones lived in the woods in dwellings similar to tree houses and I think the bad ones lived in a temple/castle. I also seem to remember this temple being the setting for the climatic scene.
• The VHS cover used to have the kid in the middle with the two main (good) dinosaurs flanked either side of him back to back.

It definately wasn't a cartoon and I've established it wasn't Prehysteria, Clifford or a few other titles!