socket_close not working

Hi all,
  I am trying to make client server application which uses socket. I can
make a connection and can read and write on sockets. But when i close
the socket and start the application again i get the exception that the
port is already in use. It should not say it as i m closing the socket,
so it should free the port. I m using 
  socket_close(Socket).
Is there any other way of releasing the port.
Any suggestions.

cheers
Saurabh