TransformXml task could not be loaded from Microsoft.Web.Publishing.Tasks.dll

The answers provided by Dai Bok and emalamisura work fine as long as you use Visual Studio 2012. For VS 2013 this fails as well. In order to make this work with all versions of Visual Studio you should:

• Open the project file (.csproj) of the project failing to load
• Search for <Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v10.0\Web\Microsoft.Web.Publishing.targets" />
• Change it to <Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v$(VisualStudioVersion)\Web\Microsoft.Web.Publishing.targets" />
• Reload the project

That will set the correct version of Visual Studio dynamically and properly.

To get mine to work, I just copied my v10.0 folder and renamed it to v11.0, and things seems to work well from then on. That's the quick fix for now.

As this is probably not the best solution, and although it works, I was going to try installing the Microsoft Windows SDK for Windows 7 and .NET Framework 4 Windows SDK for Windows 7 and .NET Framework 4, but it is taking to long to download.