Are you trying to run the copy from a writer or from an ordinary cd/dvd rom? If from a writer, you'll need to enable hide cdr media or a similar atip hiding utility for the copy to work.
Further, C&C Generals is safedisc 2.8 protected and ccd isn't reliable with that version of safedisc protection.
If ccd fails, try alcohol or the discdump/fireburner combo. Either should work with a 2 sheep writer. Alternatively, use ccd to make the cd image but with a cue sheet and then use the cue sheet to burn the image with fireburner (using dao16 or dao96). That should also work with a 2 sheep writer.