Rear sprocket help

Ok here is my situation:

1st wheel on back was the original rim that came with the bike, the sprocket fit on it fine and was lined up perfectly with the engine, I didn't have any problems with the chain jumping off w/o a tensioner. That rim has long been dead, a piece of metal grabbed into the spokes off the road and that was the end of the rim. Thank god I wasn't going too fast. Anyway, I got a replacement rim from Scheels and it seems to be ok, but one small problem. My sprocket now seems to be sitting 1/4" too far out from the engine sprocket so the chain is jumping off to the inside between the spokes and sprocket. I don't have a dished sprocket, it's a kit I got from dax a couple years ago. Is there a way I can try to move the sprocket in toward the spokes more? A different rag washer I can use on the outside or some other material? Is there a way to adjust how the rim sits in the dropouts? CAn I adjust the nuts on the axle at all to move the rim left or right in the dropouts? Any help would be great. I would love to not have to use a tension pulley as I didn't need one before this rim came along.

I'm using the wider #41 chain and the sprocket is riding on the outside edge of the chain and I think it's catching on the teeth a little bit causing the chain to jump off between the sprocket and the spokes. Yes, it's a flat dax sprocket, not dished. I may just have to get a dished sprocket. I don't really want to mess with trying to thin down the outer rag washer.