So that was the problem? Wrong privileges?

For anyone making InstallShield setups, the script code to check for this at the beginning of the setup is as follows:

if ( Is (USER_ADMINISTRATOR, "") = FALSE ) then

    MessageBox ( "Sorry, you do not have administrator

          privileges on this box, you cannot

          install the software.", SEVERE );

     abort;

endif;

Dunno if that works in the latest InstallShields or not...