With the help of Protospace members Aleks R, Chris B, Matt F, Nick B the Shorter, and Steve T, I tested my rocket tonight around midnight. We tried all sorts of things including different starter fuels (both butane and naphtha, along with some sawdust), different igniter positions (in the back, in the front, and in holes drilled in the sides), and a different igniter (electric flyswatter instead of BBQ igniter). The last test resulted in some flame inside the motor, but it didn't ignite the PLA fuel grain.
I ended testing around 12:45 am (MDT) so I could submit to the Instructables 3D Printing Contest (deadline 11:59 pm PDT). I submitted about one second before the deadline, and it confirmed my entry, but the contest entry list doesn't include my entry, so I'm going to inquire about this. Hopefully it ends up getting accepted; Protospace really needs another good, useful, and reliable 3D printer.
Without further ado, here are the four test videos I uploaded. We did lots more tests, but nothing really interesting happened.