While supporting Microsoft Dynamics for CRM, I was recently quite surprised to have to associate role membership permissions within Reporting Services for users of what I could only assume are extended properties, because up to this point I had thought permissions for reporting services were handled on the database engine side only. However, under OrganisationName_MSCRM and properties you will see the following Role Assignment options.

The link to your own Reporting Services instance should be the following for the above page:
http://REPORTSERVER/Reports/Pages/Folder.aspx?SelectedTabId=PropertiesTab

You might also run into this error, and the above Role configuration should help you fix that:

Reporting Services Error 
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• The permissions granted to user 'USERNAME' are insufficient for performing this operation. (rsAccessDenied) Get Online Help 
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SQL Server Reporting Services