KB934757 (http://support.microsoft.com/?kbid=934757) has been released
When you open the Web Application Editor - ApplicationName dialog box, and then you click Start capture to monitor a Web browser session in Microsoft Systems Center Operations Manager 2007, the Web page opens as expected. However, when you click Record, you receive the following error message:
The requested lookup key was not found in any activation context.
You experience this problem if the following conditions are true:
You install Windows Internet Explorer 7 on the computer that is running Operations Manager 2007.
You do not restart the computer after you install Internet Explorer 7.
To resolve this issue, restart the computer after Internet Explorer 7 has been installed.