The problem of kio_http is that the variable m_bufPOST (file kdelibs/build/kioslave/http/http.cpp ) is null only in the first request; so the other request fails ! The problem is in the HTTPProtocol::sendBody() at line if ( !m_bufPOST.isNull() ) so if you change this line with if ( !m_bufPOST.isEmpty() ) all works fine! Tony Aloisio