Easy cd 5 doesn't burn cdrw

hi,
i was trying to burn some mp3 from NEC 2510a dvd burner and it gives me a box saying “This is an ultra-speed cdrw. your drive cannot write.”
it is not ultra speed?? it’s just 4x cdrw but the computer reads from the same kind cdrw that i had burnt before.
weird
any suggestions?
thanks