OK, so whenever I try to capture I get a BSOD with the DRIVER_IRQL_NOT_LESS_OR _EQUAL message with the trap occuring in ew.sys. I am using a WaveterminalL card that behaves just fine in all other audio applications. I have tried two different versions of the Waveterminal driver with the same result. I have tried several different instruments with the same result. I can record to Cool Edit while piping a sequencer through GS3 without any problem. I can pipe the sequencer through GS3 with lots of effects etc. and there is no problem. The only time the crash occurs is trying to capture via GS3. This happens whether or not I'm sending midi via the keyboard or the sequencer (Sonar in my case).
All of this this points to the GS3 capture function as the root cause. Other system details:
2 Ghz Athlon
1.5 Gig memory
Windows XP Pro Sp2
(system is not overclocked and generally rock solid in all other apps)