I looked for a long time to try to find a way to hide the toolbar in an RDL file which I was surfacing in a pageviewer URL. Over and over, I found references to adding this parameter to the URL:
However, that did not work for me. But finally I found the answer.
As it turns out, that probably will work when viewing SSRS reports through a regular ReportServer, but since I was viewing it in SharePoint it was different. In SharePoint, by default, it uses the RSViewerPage.aspx page (in the SharePoint root/hive). That page uses a report viewer control on the page, so the syntax is different. All you need to add, parameter-wise is:
Capitalization is used here, but necessary.
All Things DotNet Discussed – Winforms/ASP.Net/SharePoint/WPF