Some days back, we had this issue where suddenly the Home Page icon vanished from our DEV environment and the role center page won't load up in Dynamics AX thick client.
1. Googled the issue and thanks to Brandon my friend who experienced similar problem and highlighted it in his blog http://dynamics-ax.blogspot.com/2010/06/dynamics-ax-2009-home-page-icon-missing.html
2. But unfortunately, the above troubleshooting step didn't apply in my case, as the upgrade checklist was up to date, but it definitely helped me as it gave me a clue to check out the EPGlobalParameters Table
3. Opened the ECPGlobalParameters table in AOT and found that the GUID for the URL was pointing wrongly to some another EP site.
4. Updated the GUID to point it to the correct EP Website and that did the trick!