BFD2 is the Fxpansion drums, "Best F*ing Drums #2". It has an audio export feature that is supposed to render to a file, similar to recording but it is taking its samples, through effects, and rendering them to a new wave file. The glitches were effected by the buffer and some other settings, so I knew it wasn't simply too hot a signal. But the glitches turned out to be an error in some math in their code, and it particularly started after a minor upgrade. Still, a very good product if you have patience and want to tweak your drum sounds.
I think starting the new session was a good idea, and you are right, if all you're doing is recording the Axe, the Axe USB driver should be good enough and should not conflict with another audio driver - at least in my PC this isn't a problem. Almost all Windows computers have built in audio cards, so I was assuming your Mac had at least one. I also have had computers where I had added a pro audio card, and still had the original non-ASIO card running for use with my programs that don't see ASIO. Some programs wouldn't let me have both turned on, and some programs I concluded simply 'forgot' to address the possibility of having the second audio card, and gave me money back due to the conflict which resulted in dead silence when playing back video. I read a disclaimer later that said their product didn't work with more than one audio card installed. Another time I had a laptop and planned to occasionally plug a USB audio card into it, and when it uninstalled each time I unplugged it I called the company, they said it was not designed to be removed. "You are supposed to leave the thing plugged in at all times..." I said, "you're kidding, right?". How stupid is that, like whenever you boot your computer it must see the audio card or it uninstalls it!!! I've also been amazed to get different quality of recording for no apparent reason sometimes, like with two DAWs not yielding the same audio quality, one sounding more muffled, even though the settings were as near to equal as I could figure. These are just some issues I've seen with audio cards and audio rendering that I didn't expect.
Oh, another issue I had was that my last computer had a wireless transmitter that interfered with the audio card, and was creating noise because the processor was grinding to a halt every half second or so. If you think something like this is going on you might find a program like this windows one
DPC Latency Checker for your Mac. Its just a latency checker, and if there is interference or some other reason your computer is not running steadily on all cylinders these little gems can help pinpoint that. Also I use a free program
Vista Services Optimizer - Free Download Optimize Windows services easily and safely to unload unwanted services, again, maybe Mac people have something like it although I don't think you guys need it as your operating system is probably not as clutsy.
So I feel for ya, man. Hopefully the clicking will stop. Please keep us informed.