There is an issue with Internet Explorer 8 and Adobe Flash browser plugin that causes graphs/charts not to show up in OBIEE 11g.  This is not the same as the issue that can be resolved by setting the thousand place separator property. 

The versions that have the issue are Adobe Flash 11.8.800.168 and IE8.  The same Adobe release works fine with IE9 and also works great with Firefox.  So users on those browser versions would not have been affected.

The good news is … Adobe released an emergency release within 3 days of this problem release.  The new version is 11.8.800.174.  After downloading and installing this version, we were able to see all graphs/charts.   

You can access the latest and previous Adobe Flash versions here …
http://helpx.adobe.com/flash-player/kb/archived-flash-player-versions.html#main_Archived_Flash_Player_versions_for_developers

Good luck.