There is another issue which especially happen if the
visitor reloads the page and gets a '500' instead.
Until now this happen only with MSIE for unknown reasons.
Sometimes a couple of requests are possible, sometimes
only 500 even on multiple tries.
The problem cant be reproduced with Mozilla 1.4, NS4.8,
NS7 and Opera 7 so its probably just another protocol
violation of MSIE.
Url for testing at <http://18.104.22.168/> which directs
to a nearby webserver.