Bruce,
It was my issue that had the one app with two servers - 1 HTTPS and 1 HTTP- on the same window. This created error -12263 in the clients browser whenever the request took too long.
The workaround you gave me was to remove the HTTP server, and just use the HTTPS.
And I must say, I haven't seen the error again since then.
So the thread was via email around 14-Mar-08.
Cheers,
Alan