ND3520 doesn't recognise dual layer discs

NEC ND3520a has been burning regular dvd’s ok, with either Nero or X Copy.

Just forked out for some dual layer discs and it isn’t recognising them.

I’ve had a browse through previous forums but can’t seem to find this issue.

Advice appreciated

Sorry. I think this is a problem with X Copy. Nero is recognising the dual layer disc.