Can you please send us the Visual Studio project you are trying to import to support at advancedinstaller dot com, without the source files? Also, are you using the Express or Professional version of Visual Studio?
I'm getting the same error: "Failed to start Visual Studio. Error: Invalid class string"
In my case, I get the error when I try to create an installer for my Visual Basic project. I have selected the *.sln from my project folder but I get this error. I have Visual Basic 2010 Express
Thank you for your interest in Advanced Installer.
I'm afraid we cannot import projects created with an Express edition of Visual Studio. In order to be able to import your projects you should use at least a Professional edition of Visual Studio.