The Yamaha AN1x Synthesizer mailing list

I know it is redicolous but listen:

C6 midi note through midisport usb mode does not response. Any lower 
or upper note plays nicely but this one doesn't! Why? Do you have 
any ideas? My configuration is A90ex, an200, esi4000, midisport 8x8, 
Cubase VST/32. When I switch to the thru mode in midisport panel it 
plays but all channels, on the USB Mode C6 is quiet!!!
Of course the most painful is I cannot hear my an200 at this note!

Any ideas? Maybe I should change something in Cubase?
Help me please,
thanx
Piotr