Problem with cache and 404 error

Hi,

I have an IW application which is sometimes called with a parameter in the URL.

https://mycompany.com/$/start/myparam

The first time I call this it works fine. In the ServerController the BeforeDispatch event is called, then AfterDispatch, then UserSessionBaseCreate,
then ServerControllerBaseNewSession, then the main form is displayed.

But, the second time I call it only the ServerController BeforeDispatch and AfterDispatch events are fired. Nothing else. Then the browser displays a 404 error. If I open a second tab in the browser and clear the cache I can return to the first tab, refresh it and everything is normal.

In the ServerControllerBeforeDispatch event, I am setting aReply.AllowCaching to false. I've also experimented with including the following lines:

//  aReply.Headers.Add('Cache-control: no-cache');
//  aReply.Headers.Add('Cache-control: no-store');
//  aReply.Headers.Add('Pragma: no-cache');
//  aReply.Headers.Add('Expires: 0');


None of them make any difference. Subsequent calls to https://mycompany.com/$/start/myparam result in a 404 error. This lasts until either the browser cache is cleared or the IW server is restarted.

Any ideas?

Thanks,
Tim