Likely that the disc eiether hasn't been set for a boot config or has an error in the MBR and needs to be checked for errors.
There was no errors they were 100%, and yet it says boot block checksum error?
I don,t suppose there is anyway of seating it for a boot config?
It seems i am going to have little success of getting many of the discs to work.
Its a pain that most of the discs from this batch are getting 100%,but getting that boot error message.
I could understand if they had errors.I have just got this one to work but it is a German work bench disk