Please help new at this??

[UMLQQKIN]

i have a mod chip installed in my playstation and i have a burnner also i am useing nero software i burnt a couple of games already and they worked fine but i went to copy another game today and it didnt record the game i got a error message that said:could not perform end of disk at once: what does that mean is there something that i need to do i copy on the fly with nero and the game i am copying is medal of honor underground please help? jason