"An error occurred when loading the task sequence"
I tried rebooting the problem site server but still no luck. According to KB2468097 this is caused because the BDD_* WMI classes are no longer correctly registered under the \root\SMS\site_ namespace in WMI.
- Close all of your remote and local SCCM admin console sessions
- Log on to your Configuration Manager server and select Start -> All Programs -> Microsoft Deployment Toolkit -> Configure ConfigMgr Integration
- In the Configure ConfigMgr Integration wizard, select “Remove the ConfigMgr custom action definitions” and then click next to remove all the definitions
- Re-run Configure ConfigMgr Integration again, and select “Install the ConfigMgr extensions”