[Serusers] sorry -- cannot open fifo

[Madan]

hi
why do i get this error while web provisioning l

sorry -- cannot open fifo


relevant part of my config.php

$this->web_contact="sip:xyqw at sip.net4india.com";
//address of pseudo sender
                $this->fifo_server="/tmp/";
//path to fifo server
                $this->reply_fifo_filename="ser_fifo_".rand();
                $this->reply_fifo_path="/tmp/".$this->reply_fifo_filename;


i would appreciate any help

regards,
Madan