If I am not mistaken you also have Visual Studio 10 installed, right? It seems that one of its extensions has a corrupted path, which prevents an extension that supports Visual Studio 10 as well to be installed. If you have AppBuilder extension for Visual Studio installed could you first uninstall it manually from the extension manager from all you Visual Studio versions. And then try to install AppBuilder.
If this does not happen could you export the following registry key "[HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\10.0\ExtensionManager\EnabledExtensions]" and send it to us. It contains all installed extensions you have for Visual Studio 10 and we can inspect whether any of them has a corrupted path.
Your help is highly appreciated!
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