Emacs sqlplus disabled

I started using sqlplus for emacs. It works great, except for one thing - very often I get the message "Buffer ... is not talking to anyone." The sqlplus.el file has the following code that checks (get-buffer-process process-buffer-name). How can I keep the sql process running?

(defun sqlplus-verify-buffer (connect-string)
  (let ((output-buffer-name (sqlplus-get-output-buffer-name connect-string))
    (process-buffer-name (sqlplus-get-process-buffer-name connect-string)))
    (when (not (get-buffer process-buffer-name))
      (sqlplus-shutdown connect-string)
      (error "No SQL*Plus session!  Use 'M-x sqlplus' to start the SQL*Plus interpreter"))
    (unless (get-buffer-process process-buffer-name)
      (sqlplus-shutdown connect-string)
      (error "Buffer '%s' is not talking to anybody!" output-buffer-name)))
  t)