Hi John,
Actually Mark's answers are already complete. Just want to say I faced similar problem but not as severe.
I can't remember the error number during the installation of my application at that time. Anyway the error came from the diskette (bad sector). I tested by installing from netsetup and from harddisk (in form of disk 1,2,3). That worked and verified the validity of installation files.
Rojvachiranonda N., M.D.