CRM 2011 is designed to work with:
Make sure you are using the correct version of Visual Studio to edit reports, either Visual Studio 2008 or Visual Studio 2010 or even better use Visual Studio 2012 and SSDT-BI to edit Report files .
The benefit of using SSDT-BI is you will be able to target SQL Reporting Services 2008-2012 without having different versions of Visual Studio installed.
SSDT-BI can be downloaded from: http://www.microsoft.com/en-au/download/details.aspx?id=36843
History
CRM 3.0 is in .NET 1.1 so it was designed to work with:
Tip #1: Do try to use SQL 2005 if available - it is marginally faster.
Tip #2: Don't try working in VS.NET 2005 - there are workarounds but they become very, very painful.
Tip #3: SQL Reporting Services and the .rdl files are not backward compatible - there is no hope of doing them in 2005 and back porting the RDL.