Frame Advance stopped working

[Rew]

I've been playing A Link to the Past on the Snes9x emulator the past few weeks, capturing screenshots for a guide I'm writing. The Frame Advance feature has been very helpful in this regard, but yesterday it just randomly stopped working. I had it set to F on the keyboard and now it doesn't work. I switched it back to its default key of \ and still no success. I didn't change anything on my computer or on the emulator itself, so I have no idea why this has happened all of a sudden. It just seems so random.

Any help?

EDIT: Oh, and before anyone suggests it, yes I restarted my whole computer, and still the problem persists.

[OV2]

What happens if you use the corresponding menu entry (emulation->frame advance)?

[Rew]

I tried that, and it just pauses the emulation (as in, when you return to the menu, the "Pause" selection has a check mark next to it). And you still can't frame advance.