Hello Scott Russell,
Actually this is related to Sitefinity indeed. The file which we point out:
is part of the IIS6/6 installation, which means that we will not add it to the system. When the project manager is being installed, the installer reads this IIS5/6 file in order to check where to install the project manager.
In our next version, you will be able to install Sitefinity to any location. There are a lot of improvements in this area.
I hope this helps!
the Telerik team