Inside the .vbproj file there is a path for the local host, most likely something like http://localhost/dotnetnuke
You need to ensure that the local host path is actually
where module name is the folder name that the solution you are opening is in. Once you make this change manually, if you open the project in 2008 it should successfully upconvert for you. This has at least worked for me in the past with that error.
Microsoft C# MVP, MCITP
Director of Development
for .NET and DotNetNuke info
Author of "Professional DotNetNuke Module Programming"
Tech Editor on "Visual Studio 2010 six-in-one" and "Pro C# 4.0"