Amana gas dryer won't ignite

I purchased a used Amana gas dryer. After installing the dryer, it ran fine for 3 loads and then proceeded to run all night on the auto dry cycle. I pulled the front cover and found that the igniter will glow but it appears no gas is getting through. I pulled the regulator unit and inspected the screen thinking that some dirt may have clogged the orifice. The burner area was pretty dirty so I blew it out and vaccuumed the unit. Still no ignition. What would be my next step in the diagnosis of the problem? Any help would be greatly appreciated!