I am really struggling with this issue as it seems to occur randomly for me. When I call,
Desktop.browse("some url");
Internet Explorer will not display. The exception message is as follows,
The requested lookup key was not found in any active activation context.
When it occurs it occurs consistently until I restart the machine, but it eventually occurs again.
The workstations that seem to have this problem are running Windows XP with Internet Explorer 8 set as the default browser.
EDIT: I forgot to mention that if I open up Internet Explorer directly and navigate to the URL in question then it will work fine.
EDIT2: This seems to happen if Desktop.browse is invoked and then is called again at least 15 minutes later. Restarting the application now seems to fix the problem.