Don't put him in a separate container to eat if you just got him. He's already stressed out from moving into his new home. If you put him in a new tank to eat this soon he probably won't eat.
You can take the hind legs off the crickets so they can't hop around and instead of just placing them in front of him, kind of put them off to the side and nudge them to crawl forward. Pacman frogs' feeding response is triggered by motion more than anything.

Mine had problems with eating cocofiber as well. Generally cocofiber is safe for them to accidentally consume in small amounts, but can be a problem if they eat a lot of it. The general rule for leaving crickets in the tank for the frog to eat is no more than an hour or so. You may have to do this if he doesn't eat with you placing the cricket there. Like I said, he's probably already stressed from moving, and might not want to eat when with people around.