On my dev system I VS 2010 installed, followed by the VS 2012 beta. I had to uninstall that at one point do to a confliction with CodeSmith and the .Net 4.5 Beta. It seems after that my dev systems is missing a few dlls and I specifically need the 'Microsoft.ReportViewer.DataVisualization.dll'. I've checked the 'C:\Windows\Microsoft.NET\assembly\GAC_MSIL' path and there is no 'Microsoft.ReportViewer.DataVisualization' folder. Is there any other way I can go about getting a copy of this dll?
Have a look in the windows SDK folder:
%PROGRAMFILES%\Microsoft SDKs\Windows\v7.0A\Bootstrapper\Packages\ReportViewer\ReportViewer.exe
It should install the required dll.
Edit
More information here.