Creating Modules (BASS Mod)

I have a question i have try to modify a music (MOD) volume with

BASS_ChannelSetAttributes(ID,0,Volume,0)

But this function return an error ? any idea ? It is the good command ?

The old command : BASS_MusicSetVolume(MusicStream,50)

Seem to be forget ?

And another question :

I have try to check the data channel with this stuff :

Global MYBANK:TBank=CreateBank(1024)
BASS_ChannelGetData(MusicStream,MYBANK,BASS_DATA_FFT1024)

But the program crash ?