The noise reduction profile is channel-specific. A profile made from single channel audio won't be recognized for stereo, and
vice versa.
Thanks for the reply. Yes, I discovered that it's channel dependant when I used AA2, but with v3, I seem to get the error all the time, even when the channels are clearly the same (i.e., profile was saved from a stereo sample and current file is selected as stereo). I have to recapture a noise profile each time I use the noise reduction plugin. It simply will not work with any stored profiles. I thought at first it was because I was trying to load a profile created in AA2, but once I tried loading a profile I'd just created and saved in 3 yet it wouldn't work, I knew something was wrong.