Can't open solution file in VS'03...suspect IIS

Greetings:

Installed the source code version of DNN 3.2.1 and it went uneventful. However, upon clicking the DotNetNuke.sln, I'm bombarded with error messages for not only the solution, but each project in it.

"The application for project http://localhost/DotNetNuke/DotNetNuke.vbproj' is not installed. Make sure the application for the project type (.vbproj) is installed."

I've checked and re-checked the paths in the vbproj & webinfo files as well that the alias virtural directory in IIS matches my folder holding the source code.

I suspect an IIS issue only because upon using the file selector dialog in VS '03 to open a solution file, it's virtural directory doesn't appear there as other virtural directories do; it's like it doesn't recognize that it's there.

Any and all guidance and advice will be greatly appreciated.

Ed in Tampa