One Plug Won't Play, but another will...

[hill56871]

Okay, I'm minding my own business, recording on my new Live 7 upgrade, and my Gearbox plug-ins stop playing. Signal is going through, as indicated by the signal level bars to the left and right of the plug box at the bottom of the screen, but no sound. The plug is enabled. My Waves plug in the same chain is playing just fine. Gearbox isn't playing anywhere else, either. Has anyone run across this with a plug, and how did you get it to work again?

I'm using Live 7 on an Intel Imac 2.8G, with an Axiom and a Korg Nano pad for midi input, and a Presonus Firebox for audio in.

The only new component is the Live 7 upgrade.

Thanks for any help.