I dont have a gas smoker, however i have several single burner hi and lo output stoves. one of the stoves i purchased had the same problem. there are two ways to deal with the problem if you can disconect the hose from the burner.
if you need it right away you can go to a bbq/grill supply store, a sports store like cabelas or sportsmans warehouse, etc. or your local propane company and get a new tank connection and hose.
or
you can send the piece back to the company with a description of the problem and ask for a replacement part.
why only these two ways to solve the problem?
Because as I found out with my problem, only the manufacturer can make the repair because they have certain certifications to make the connection in the first place. It sounds like you are just missing the rubber gasket which still needs to be sent in to get repaired. if youre missing the gasket a gas company may beable to slap one on for you, if its that easy.
I went to my local sports store and bought a new hose, regulator and tank connection because i needed it right away. I sent my faulty assembly to the manufacturer/retailer i got the stove from and they gladly replaced the broken piece. yes i now have an extra but now i have a back up or another assembly for a stove i can buy at a flea market or garage sale, etc. that doesnt have one.