@blablub
If you were having problems installing the original Disc onto your computer I would tell you to contact the games Tech Support. They would try to help you as it is the original disc.
Now, you contact Tech Support and tell them you are trying to install a 'backup' of the game onto 'your friends' computer and let me know what they tell you!?
I think you may find the response they give you will be very similiar to the response I have given you!
To help you with your problem, one of the first questions I would normally ask you is "Does it work when trying to install from the 'original' disc?"
Now as you say you are at your friends house 'without' your original disc, you wont be able to answer me on that one!
See your problem is it may not even work on your friends computer when using the original disc?
So, once you have contacted the games Tech Support please let me know what they told you the problem was. But I am guessing, they will tell you to "install it from the original Disc and not from a copy!"