DSS Installshield Wizard - "Setup can not run on this machine"

For those that read my post yesterday, apologies, it might not have been completely accurate.

But now facing a new problem. After reformatting / installing OS on my brothers Dimension 3100C, I stuck the 'Driver disc' in the machine, read the blerb about the order in which to 'download'/extract the drivers. And as recommended, tried to install DSS first from the ultilities section. Things seem to be going well……"Preparing Setup - Please wait while the InstallShield Wizard prepares the setup"…..

But then get the error message "Setup cannont run on this machine".

Any opinions? Should I have installed something else first? Eg "Miscellaneous Ultilities - Dell OS Tools Rev A01"?

Many thanks,

Chris.