SPSecurity.RunWithElevatedPrivileges launch the code with the administrator account of SharePoint.
Thought it could tell you during the execution : “Access denied” or :
UnauthorizedAccessException was unhandled by user code
Make sure you have sufficient privileges to access this resource. If you are attempting to access a file, make sure it is not readonly…
Make sure you re-open a new SPSite inside the SPSecurity.RunWithElevatedPrivileges in order to get the authorization of the administrator.
Example in a feature receiver :