AX 2012 - SSRS - The permissions granted to user 'DOMAIN\USER' are insufficient for performing this operation. (rsAccessDenied)

Hi people,

When running reports from admin accounts they run fine. When using non-admin users I get:

>>Error while setting server report parameters. Error message: The permissions granted to user 'DOMAIN3\USER' are insufficient for performing this operation. (rsAccessDenied)

The permissions granted to user 'DOMAIN\USER' are insufficient for performing this operation. (rsAccessDenied)<<

A google search lead me to: http://daxdude.blogspot.mx/2012/01/ax-2012-ssrs-error-error-while-setting.html 

I've already covered step 1 - Navigate to the Report Manager url (http://SSRSREPORTSERVERNAME/Reports/Pages/Folder.aspx), go to the Folder Settings and click on 'New Role Assignment'. Add the appropriate user or group. Make sure they have access to 'Browser. Content Manager, and DynamicsAXBrowser'. Step 3 does not apply, UAC is not enabled.

I'm stuck with step 2 - IIS: Check to make sure the Reports virtual directory is NOT set to allow anonymous access on the properties (VirtDir > Properties > Security).

Has anyone faced this issue?

Thanks in advance and Knd Rgds

##

Setup: AX 2012 FP + CU3, Windows  Server 2008 R2 Entreprise SP1, SQL Server 2012