I'm by no means an expert, but in my limited experience of commercial baby food it tends to be a lot more bland tasting than home cooked food. Might it be the case that he's not used to yummy, natural tasting food any more?
My suggestion would be to go back to the beginning, as if you were weaning him all over again. Puree single fruits and veggies and mix them in with baby rice. If he takes to them, then start combining tastes to they get more complex.
Good luck with it!