Louey;
This is strange because I also bought the aquamedic regulator from inland, bought "ice maker" hose from HD, and hooked it right up. The LDPE (ice-maker) hose fit perfectly into the J.G. fitting on the bubble counter, and onto the barb on the regulator. I had to squeeze a bit to get the nut on the LDPE hose, but once the hose was on the barb, the nut screwed in fine.
My guesses are:
1. You don't have the same size LDPE hose that I'm using, or
2. There's a different barb, or you're not finding the right barb, on your regulator. It's 90o counterclockwise from the needle valve; as you're looking at the dials, the needle valve is down and to the left, and the barb is down and to the right. You take off the nut, there's the barb.
Matt