How can I restore propane flow to my gas grill?

Our gas grill worked fine last summer, but we just recently ran out of propane and got a new tank. We hooked it up as always, opened the tank valve, turned on the burners and... nothing happened. Even with the tank valve all the way open and the burners set to ignite, there is no gas coming out of the grill. I can't see anything in the tank or the hose that resembles a blockage, and I'm not sure where a blockage could occur. It's a CharBroil QuickSet grill, and I'm using a Blue Rhino propane tank. Any advice?