Hi Grayrider,
both methods, automatic and manual install are working fine. I tested them both several times.
Automatic install is the easy way...
If you want to do the manual install you should be aware askd by the installer two times:
First:
the installer asks for the FSX route folder in your system. This was the question you did see when trying the manual install.
point the installer to yout fsx main folder and confirm.
second:
after that the installer asks for an existing temp folder of choice. If you do not already have created a temp folder the installer will create a folder for you.
point the installer this temp folder ( in your case, the folder you already created) and confirm.
the installer will now copy all necessary file into this tempt folder.