We recently upgraded our web applicatoin to Visual Studio 2010 and Crystal Reports 2010. Now when ever a report is run in our report viewer (using CrystalReportViewer) we get an "Object Reference Not Set to an Instance of an Object" while the report is running. Once the datasource has binded to the .rpt successfully (10 seconds) we get the error message "Value cannot be null. Parameter name: inputString". The odd thing about this error is that I am unable to reproduce these issues on a web server that has the 2010 web application deployed on it with cr2008sp2_redistinstall and CRforNET40_x86 (SP2 and x86 Runtime) installed. I have a feeling that our developer boxes are missing something.