Hi. I think I found the reason for your crash. In the renderer.cpp file, we create the mlt producer but never test if it was successfuly created. Mlt has an is_blank() function to test this.
I will commit the fix as soon as I fix my indent. :-) By the way, you could maybe try renaming your .avi file in .dv. On my system, a small clip grabbed with dvgrab was unreadable by mlt when saved with a .avi extension, but loaded fine if renamed it with a .dv extension...
