While client is sending a request to a server, it may respond with interim "100 Continue" response which means that server received a part of the request and is ready for more. Currently cURL network backend in OWB reacts inappropriately to "100 Continue" response by calling didReceiveResponse() with no content type, content length etc.
I found this problem responsible for Yahoo mail sent confirmation screen failing to load and XOOPS CMS forum post message operation failing to redirect properly (for example on http://aros-exec.org).
I guess instead OWB should simply ignore 100 response and wait for the real one which has to follow "100 Continue". Alternatively we could fix the problem by removing from request headers "Expect: 100-continue" that cURL sends by default. I will attach patch with the first solution later.
