nero 5048 does not want to read cd

i am trying to make a cd-copy of an original word 6.0 cd. cd seems to be ok. i used it and checked it with 2 programs. but i cannot make a cd-copy with nero 5048.
i will now recheck my winme. after having done that i will try the same on a second hd with nero 5518.
should i use cd-iso or cd-image-feature? this error does not occur on other cds. i cleaned it maybe i have to “repair” it.