RDLC命名空间引用错误的解决方法

The report definition is not valid.  Details: The report definition has an invalid target namespace 'http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition' which cannot be upgraded.

Turns out the issue was my "C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v10.0\ReportingServices\Microsoft.ReportingServices.targets"  file had somehow changed.  The top of my file was:

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <UsingTask TaskName="Microsoft.Reporting.RdlCompile" AssemblyName="Microsoft.ReportViewer.Common, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>

And it should have been:

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <UsingTask TaskName="Microsoft.Reporting.RdlCompile" AssemblyName="Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>