[lesfix]

I made my backup copy of Doom3 from my 3xCD's to one DVD-R and it worked. Everything installed and run correctly.
First copy all files from CD-1 to a Hard drive folder, then copy all the .pak files from the folders in CD-2,CD-3 and save them to their correct folders on HardDrive folder. Don't copy anything else from CD-2 or CD-3.

Now, replace the Doom3.exe with a 'No CD' version'.

Then in a Hex Editor open the Doom3.msi and search for text.... DOOM3_1
This is relevent to your problem because there is only one reference to each CD in this. I found the three CD's named as DOOM3_1, DOOM3_2, DOOM3_3
so I renamed them all the same as DOOM3_X and saved the Doom3.msi file.
( I did do searches for other CD name reference but only found the above)
This should work for other games that use xxx.msi and load several CD's.
Don't change the length of the edited names or you will get an error when run, and just make the edited names the same one as the Volume label of the DVD you are going to make.

Now load up Nero and make the DVD ISO, (I first used a DVD-RW) label it as DOOM3_X
Then copy all the files to the compilation and Burn the DVD.

Les