Check the CD for scratches ALONG the line of the track on the "silver side" (i.e. not middle to edge, but "sideways"), a supposedly superficial one can be dog's for a CD.
If there is one you can use Brasso or toothpaste to polish it in the direction MIDDLE TO EDGE.
Also, check the LABEL side of the CD, if there is a scratch here, you have a 100% coaster.
You could also try a "disk grinder" like Skip Doctor(tm) for silver-side scratches.
Of course, as you said, easiest to get someone with a CDRW to run off a copy (at 4x or less if you have a 4x drive)!
Finally, try another Amiga CDFS? I have found both AmiCDFS2 and CacheCDFS to be excellent, but the CBM one was cheeks. I did have problems here with the default one pre-OS3.9 versus the above CDFS' with some magazine CDs...
