The model you have listed shows it uses this type of ignitor
If this is the case then it still could be the problem.
Ive had many cases where the ignitor would actually
lite and still be the source of the trouble. In fact
there werent too many of them that were completly dead.
"Not in 100 percent of the cases" (but generally) I found that
if the ignitor did actually come on at all the valve itself
was ok. What happens is that these type of (or glowbar) ignitors
can get weak but still operate. The valve is connected in series
with the ignitor, so if they are weak they wont allow enough
electric current to pass through the valve in order to either
open it up to let the gas in or to keep the valve open so that
it stays on.
In short the ignitor is most likely the culprit.
Hope this helps