If you have any other computer available, try to copy all the 30 .gho discs on the available hard drive. Norton Ghost Explorer is very "moody" and "stubborn" if doesn't have all the discs visible simultaneously. So, if you have like only 2 discs and 2 CD-ROM drives is OK to load a disc in each. But with the 30 of them you need to copy all of them to a hdd and after that try to open the image with Ghost Explorer.
Good Luck.