Hi Splitpin
I've found that the trick is with having Multiple DVD installation disks with large source .CAB files
The installer needs to have all the source .CAB files in the same directory location for the installer to read and compile them into the program.
Suggest instead of attempting to run the install from the 1st DVD create a Temporary Directory Folder
1st open your Windows Explorer go to either your Documents folder or Downloads folder. Anywhere will do, whatever your comfortable with.
Right click locate New and click Folder give it a name for example call it "Rex 4" then copy the entire contents of the 1st DVD into that new Folder call Rex 4
Repeat process insert 2nd DVD and so on until you have all the DVD's files copied into the one Temporary Folder location.
Then remove the last DVD from the drive slot.
Go back to the Temporary Directory Folder called Rex 4 locate the file "cdinstall.exe" right click on-it and "Run as Administrator" to install the Rex 4 program at some point you will require the REX 4 Licence Key so you will need to have that on hand so you can enter and complete the installation process.
This is how mine looks only I have a downloaded Texture update zip file and extracted file to keep them all in the same Temporary location on a back-up drive.
