In general, I believe publisher-specific files should be installed to a publisher-specific location; for example, from the Windows XP logo guidelines (I don't immediately see a quote in the Vista guidelines):
Shared components that are private to a single software vendor must be installed in one of two places. Do not store these files in the System directory.
Thank you, that is what I suspected. However, the developers I am working with are claiming that a self-registering file they creted will only work in the system folder. This does not make any sense to me.
When installing system files like XML, I like to use merge modules for that. As you may be aware, if you go into the "Application Data\Objects" in the Install Shield IDE, you will see a collection of installable objects and merge modules available. You can go to the Macrovision web site and download more if you need to. These modules do all the necessary registration for you. So there isn't any guess work. A lot of these modules come from Microsoft. So they are already geared to be integrated into the OS without any problems. I should also mention that you can use merge modules in an Install Shield Script project as well as an MSI project. I hope this helps.
