Use correct status codes on error
When a status other than "200 OK" is returned to the client, Internet Explorer will show the user a "Friendly error message" instead of the response body. This behavior can be changed by the client, but nobody ever does. ;)
In an effort to work around this behavior, CP returns 200 even when an error has occurred. As described here (http://archive.apache.org/gnats/5173), it may be possible to correct this behavior, and use more appropriate status codes, by sending a "large enough" body (1392 bytes).