Open InstallerScript.iss
First or Second line
Code:
#define ProgramFiles "C:\Program Files (x86)\Eletronics Arts\Kingdoms of Amalur"
Delete ";" infront of this line.
Compression=none change compression to what you want, example lzma2/ultra64
Put there your game path and compile (F5).
PS: And open Setup.ini and search for MyExecutableName=FC3Updater.exe
Put there the executable of the game