Hello,
Thank you for the test. I was so surprised by your answer that in the beginning I didn't believe it and tried it on another machine... and it worked there.
We have 2 Windows 2008 R2 systems in the company.
1. Windows 2008 R2 ENG - here it doesn't work
2. Windows 2008 R2 DE - here it works!
Both systems are configured in the same way.
I'm not making it up. On the 2008 R2 ENG system it really doesn't work. I have tried everything including the main Administrator account.
Here is some evidence - I used the "Process Monitor" to check if the problem is caused by the missing rights.
Result on the working system (DE):

- Proper behavior on the 2008 R2 DE system
- result on 2008 R2 DE.png (193.63 KiB) Viewed 25169 times
Here is what I got on the not working system (ENG):

- Wrong behavior on the 2008 R2 ENG system
- result on 2008 R2 ENG.png (57.25 KiB) Viewed 25169 times
It looks that the
InstallAware is not proceeding with the installation, installutil.exe is not started at all.
I doubt that it has something to do with the language (DE/ENG versions). Something must be wrong, but what?
For now as a workaround I invoke the installutil.exe manually. And it works on both systems.
How to proceed now? Do you consider this as a bug?
Best regards,
adi