The project type is not supported by this installation

In the .vbproj file, the project types are:

<ProjectTypeGuids>{349c5851-65df-11da-9384-00065b846f21};{F184B08F-C81C-45F6-A57F-5ABD9991F28F}</ProjectTypeGuids>

Removing this line from the vbproj file changes the error to:

"The imported project "C:\Program Files\MSBuild\Microsoft\VisualStudio\v8.0\WebApplications\Microsoft.WebApplication.targets" was not found"

This file is provided by VS 2005 Service Pack 1.