Pags,
Maybe it's the rub itself. Is it a Grocery store rub or a premium, contest type BBQ rub, the photo if that's it on the right, looks like something off the shelf.
Maybe something with a little more omph? Look at the ingredient list, if Paprika is #1 or 2 (with salt probably) then it's a wasted spice. Paprika is a good filler, but I don't think it cooks into much of a flavor.