I was not able to find this specific issue in any web searches, so if this needs to be submitted to Microsoft as a bug I'd be interested in guidance as to how/where to do that. I had an SSRS 2008 report that would neither print nor export to PDF, although it rendered fine to the screen and could be exported to Excel. The print error was a generic "an error occurred during printing", and the PDF export error was "an error occurred during rendering of the report (rsRenderingError) Object reference not set to an instance of an object". The problem was traced to merged cells in which one column was hidden while another was visible. I was able to resolve my issue but wanted to share in case others are struggling to identify the source of similar errors. This is not the same issue as the "Rendering difference between SSRS 2005 and..." issue.