Prototype Collection 2xDVD9 - 4xDVD5

[pakrat2k2]

dax3, Morgrel

Select Game Directory(Select folder whereby Inside there is Prototype and Prototype 2 Folders

You have BOTH games Installed to same base folder ? IE: C:\Program Files (x86)\Activision

where Prototype & Prototype2 are subfolders ...
C:\Program Files (x86)\Activision\Prototype &
C:\Program Files (x86)\Activision\Prototype2

Then installer should work properly.. will have to dig out games & test. But in meantime, post back if you have them installed properly.