In file Freescale_BM_USB_Stack_v5.0/Src/usb_core/device/sources/classes/audio/usb_audio.c, at line 767, you have (reformatted for readability):
error = audio_obj_ptr->class_specific_callback.callback((uint8_t)GET_CUR_COPY_PROTECT_CONTROL,
audio_obj_ptr->current_interface,
data,
size,
audio_obj_ptr->class_specific_callback.arg);
EVERY other call to the class_specific_callback that involves audio_obj_ptr->current_interface is of the form:
error = audio_obj_ptr->class_specific_callback.callback(audio_obj_ptr->current_interface,
cmd,
data,
size,
audio_obj_ptr->class_specific_callback.arg);
It appears to me that the call at line 767 is incorrect, and should instead be:
error = audio_obj_ptr->class_specific_callback.callback(audio_obj_ptr->current_interface,
(uint8_t)GET_CUR_COPY_PROTECT_CONTROL,
data,
size,
audio_obj_ptr->class_specific_callback.arg);
