I had this problem with Studio 8 and it bugged me for ages, i was entering the CD key in upto 160 times, what i did may not strictly be "proper" but it works.
What i did was allocated the "Clean Machine" the Dreamweaver package that i had created earlier, i then ran the first snapshot to allow it to get all the details it required.
Once the snapshot had finished i ran Dramwaever which asked me for the CD key, i entered the CD key and clicked register later.
I then ran the second snapshot which completed the MSI and allocated it to the machines that had Dreamweaver, Flash and Fireworks 8 on this worked fine and i have never had a problem with it since.
Worth a try!
I did this in an RM enviroment but i believe it would still work in a vanilla enviroment.