My apologies Chris. I don't know if you're the first AMD64 user to try to install the tools (everybody else Intel 64?), or if something changed in the latest FTDI driver to keep it from running with the 32-bit dpinst.exe. Incidentally, I recently installed Win7-64 in a VM on my AMD64 machine, and I see the exact same issue.
All the installer really does is extract the files (pinprocfw.exe, the FTDI driver, and the pypinproc self-installing python extension) and the attempts to run the FTDI driver installation. It's the FTDI driver installation that's failing.
The good news is... the installer created all of the files you need in the installation directory. So you have a few choices:
1) Wait for me to create an installer that works for you (might be weeks or months.
2) Get the 64-bit version of dpinst.exe from Microsoft and run it in the FTDI driver directory to install the FTDI driver.
3) Install the FTDI driver yourself. You can download it from FTDI's Driver Page.
It sounds like you've maybe already done this anyway.
The last option is probably the easiest.
Then, if you have Python installed, you can just go into the ext/ subdirectory and install the pypinproc extension.
This assumes you want to create your game in pyprocgame. If you want to do it in C, you'll need to install and build the libpinproc library from source. The installer doesn't provide that anyway.
Let us know if you need more help.