MSBuild fails with VS2013

I have upgraded from VS2010 to VS2013. Not sure if related but build fails with following Error: C:\Builds\12\MyOticon-US\MyOticonQA MP\Sources\MyOticon-US\Oticon\Branches\Kaiser\UI\UI.csproj (1696): The imported project "C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v12.0\WebApplications\Microsoft.WebApplication.targets" was not found. Confirm that the path in the <Import> declaration is correct, and that the file exists on disk.1 Have changed the appropriate Project file from
<VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">10.0</VisualStudioVersion> to <VisualStudioVersion Condition="'$(VisualStudi ...