An error occurred during local report processing. Access Denied. (Exception from HRESULT: 0x80030005 (STG_E_ACCESSDENIED))
Just resolved a bugging issue I had with Reporting Services, when I tried to preview a report in the Dev environment (Visual Studio BI) I got this annoying error, on a specific report only, which worked perfectly on the deployed environment (no problems with build or deploy).
I new it had something to do with permissions, but since it basically worked, I ignored it (the problem only started today).
A quick search brought me to David's blog where the answer was written clear and simple (SSRS has a lot of these permission issues, and it's always this small bit that is wrong).