Hi there!
Sometimes I've found a odd error with UOS. I believe that problem is with the uos_InputAddDSPVolume and/or uos_InputSetDSPVolume usage between creation and releasing players.
When I debug the application, I get a error "RunError(204)" in uos.pas, at line 7148:
setlength(StreamIn[x].data.Buffer,StreamIn[x].Data.outframes)
Finally, I receive a error "Invalid pointer operation".
Thanks in advance!