hai ,
i can hear backgound sound<winds and airplane .et> but without "mine" sound in ATC!
i am sure my both ***.gvp files is OK!
so i go to Contorl Panel-->Haedware and Sound-->Sound
select a playback which in use right now,go to it's Properties,at Enhancements tab,
make sure the Disable all sound sffects is unchek!
i hope it woulld help you !sorry for my poor speaking!