Ah, sorry, didn't see the black screen bit. Apparently (according to the changelogs) pce-fast is broken on the current nightlies - I'm using the Nov 16th version myself, and have played through Rondo of Blood with it.
It could also be a screen filter (if you use those), I haven't tried it with pce-fast but filters gave a black screen on Genplus gx and pocketsnes last time I tried. Can you still hear sound, or is it compleely frozen?
I tried the oldest build available and it still doesn't work is it possible for you to upload the build you have?