Originally Posted by helsinki101
do i need to get some file more?
No. You should never have to do that. Something else is wrong.
I recommend that you first verify the downloaded ISO file by comparing its SHA-1 hash to the one in the text file SHA1SUM on the server where you got the ISO file. If you no longer have the ISO file, there is a way to generate a valid SHA-1 hash directly from the DVD that you created. If you need some help with any of that, see another thread here
After that, I would burn a new disk and have your burning software verify the data after burning.
Finally, I would use a brand or type of disk known to produce good results on your equipment (both writing and reading). I promise you that not all disks are equal. You can also try burning at less than your disk's maximum rated speed.
P.S.: I will let someone else try to talk you out of that FC4-to-F8 upgrade.