Ferret wont take treats

Question
This is my first time owning a ferret and we just got him like three weeks ago. My ferret Karn won't take treats, he eats his food ok so I'm not worried about malnutrition.  But he won't take a treat when I try to give him one.  I've tryed the treats they gave him in the pet shop we got him from, the girl in the shop said she had no trouble and that he'd even take chicken nuggets from her (after she took the breading and everything off them) but he won't take a thing from me.  I've tryed putting it in his bowl and on the floor after he wouldn't take it from my hand.  Am I doing something wrong?  Karn will sniff what I offer him then ignore it completely, the only thing he seems to like is ketchup and other tomoto sauces but I don't think it's an ok treat to give him.  I'd like to get past this so I can train him to use a litter pan outside his cage etc.

Answer
It may just take him time to settle into his new home before he takes a treat or he may just not want the treats.  Sometimes I have picky ferrets while other times I have a ferret that will take anything.  Stay away from anything that isn't meat since they are carnivores, but you can try hand feeding him his own food or a few cat treats.