Stop wasting film, use the backing paper of a developed roll as your test roll.
The pin has to be pushed in as you try the rod n wheel thingie.
Check that the door is hitting the pin on the edge amnd making it go in far enough, common problem. Also, is the door locking all the way when screwed down or are the seals keeping it from shutting properly?... Another common DIYer mistake using the wrong material for seals.