mini lu

I think it was a problem with the computer as I tried on my friend's and it worked fine

I am using sonic stage 1.5 on windows 98se to transfer a CD to a MZ-N510. Computer records songs fine but when I come to transfer it transfers first 2 songs fine but when itgets half way through the 3rd song a dialogue bar appears saying the minidisc is full. It is not as I just put a new disc in. I have tried with several different CDs and discs and had the same problem. Is there a way I can fix this or do I need to go to sony?