After a quick check online it states the Value Edition of AF since AF 8 are likely to have ROM's with XOR encryption making the ROM file approx. 1kb larger eg 513kb rather than the standard 512kb. This is coupled with a rom.key in the ROM folder. There are 128kb and 256kb ROMs also that this would apply to.
It also states AF Plus Edition and Premium Edition since AF 8 do not have this encryption system and are unencrypted.
My AF 11 Premium downloadable package has unencrypted ROMs.
Interesting to know. So if people have Value Edition, they will have issues.