Nuts

Hello, first time I post here, so my story is, I got a mz-nh600d unit as a gift, i would like to transfer my mp3's and wma's to the minidisc, but for some reason after installing sonic stage and updates available I cannot do anything , in a few hrs i'll be making an atlantic crossing, so I would like to have some music for my flight, the only things I get, are that the unit says "no disc" even if there is a brand new 80 disc in it and after puttiing my library in sonic stage, when I wish to transfer to the unit the files from my it insists in asking me to insert a disc, everything is properly connected, but I still get nowhere... Why is it, that something tells me that I will have to make up with the hideous music selection airlines have...... , please help! Thanks in advance!