Show Cue System

I am using a video Q to feed a TV on stage and want to change the audio level, leaving the video running.
Adding a level change Q just brings up a"memory access" error message.
I am using the Realtek speaker option on my Mac Pro (OSX 7) , running Win7 in boot camp.
Any ideas how to adjust audio level in this situation, or am I just in an unfortunate hardware situation?!
The only way I can see this through is to strip the audio out and run it simultaneously with the video as an audio Q. Seems a bit arduous!
Mark

Mark,

I've tried to reproduce the error you mentioned but my level change cues work correctly, so I've emailed you details of a tracing version to run. I tested using both xVideo (in the 32-bit version of SCS) and TVG (in the 64-bit version of SCS).