Thanks peterf1999 proper conversion works for me.
But one little edit:
In step 5 you write:
Copy:
'data1.cab & data3.cab'
files from 'temp\GHOSTBUSTERS_1\Setup\' to 'temp\GHOSTBUSTERS_2\Setup\'
As you see in picture 'data3.cab' is on DVD1. I think that 'data3.cab' isn't necessary on both DVD's. I'm tested without 'data3.cab' on DVD2 and works 100%.