Thanks for the response, the casing I had was Propertygroup, your casing has solved that problem. But now I have 59 warnings all along the lines of:

Warning 1 The element 'PropertyGroup' in namespace 'http://schemas.microsoft.com/developer/msbuild/2003' has invalid child element 'CustomBeforeMicrosoftCommonTargets' in namespace 'http://schemas.microsoft.com/developer/msbuild/2003'. Expected 'Property' in namespace 'http://schemas.microsoft.com/developer/msbuild/2003'. C:\WINDOWS\Microsoft.NET\Framework\v2.0.50215\Microsoft.Common.targets 18 10 Miscellaneous Files

I have a feeling the solution is as simple as the last, but I am unable to find it.