timeek2 , Disk Error usually indicates a firmware corruption that could be due to hacked memory, or poor firmware coding.
What i'll suggest first to do is to format the player using MP3 Utilities Disk Tool, the guide and relevant downloads are here http://www.mympxplayer.org/how-to-removing-memory-hack-vt2400.html
After formatting, see if you still encounter the Disk Error problems, if so, do a Windows Scandisk on it.
As what jo gobel mentioned earlier, in fact firmware "upgrades" are not just 50/50 chance, but i'll think of it as 99% chance of bricking your player. Even if the version matches exactly, it is very likely to be different. These player manufacturers do not practice proper versions control. Usually there could be tens or hundreds different variants of the same version.