Sometimes you get this feeling of really mastering a technology. As if nothing can surprise you and you’ve seen it all. If you’re lucky, you’ll get a message like this before you become too cocky:

Error: The callee (server [not server application]) is not available and disappeared; all connections are invalid. The call did not execute.

Do you know what it means? Neither did I, but somebody else did :

It occurs in the context of pages using javascript to generate page
content and communicate between windows, one of which windows is closed.

Possibly
* page A pops up page B in the link and page B wants to communicate with
page A, but page A has been closed (possibly by you or a popup killer?), or
* Internet Explorer has become totally confused and it will work in
another browser, or
* poor page design.

Or in my case forgetting Javascript passes references when assigning objects which become null, if referenced object was stored in now defunct window. The problematic browser in question was of course Internet Explorer.