I was working on some of the built-in System Center Configuration Manager 2007 (CM07) SSRS reports when I tried to access one of the reports via Report Builder 1.0 (SQL 2005).
When I tried to open the report I received the following error message:
It turns out that SQL Server Business Intelligence Development Studio (BIDS) was used to create all of the built-in reports within CM07 and therefore Report Builder 1.0 is NOT capable of opening these reports.
In order to edit these reports yourself, you need to use either BIDS 2005 or Report Builder 2.0 (SQL 2008). Make sure, though, that your version of SQL (SSRS) is compatible with the version of BIDS / Report Builder that you are using.