I was in the process of reinstalling Enterprise Portal for Dynamics AX 2009.  After reinstalling EP, SSAS, and Service Packing my Role Center was gone and there was no ‘Home’ link in the top (breadcrumb) area of the Axapta client.  After some poking around I clicked on:  Administration | Setup | Internet | Enterprise Portal | Web sites

Look at the bottom of this screen and you will see a textbox for “Web site used to display Role Centers in the Dynamics AX client”.  If this textbox is empty (this was my case) then the Home link and the Roles Centers fail to display.  Simply copy your Internal URL and paste it into the text box.  Hit save and then log back in and viola!  Role Centers.