Here are the steps and actions needed to change the Business Connector Proxy account in Microsoft Dynamics AX after you have EP installed, and SSRS and SSAS configured for EP.
7. Open up an elevated cmd prompt and run IISRESET.EXE /noforce on all the servers in the farm.
8. Give BCproxy the DynamicsAXBrowser rights to the DynamicsAX folder in SSRS. For more information see - .http://technet.microsoft.com/en-us/library/aa496432.aspx
9. In SSAS, give the BCproxy admin rights in SSAS security.