If you are having troubles with installing/registering ReportViewer dll's
either using gacutil.exe or setup file, you can download the Microsoft Report Viewer Redistributable 2008
package from the following link.
http://www.microsoft.com/downloads/details.aspx?FamilyID=CC96C246-61E5-4D9E-BB5F-416D75A1B9EF&displaylang=en