a problem about igrep

[wangyu]

I copied the igrep.el file into the directory lisp and add the following to
the .emacs file:
(autoload (function igrep) "igrep"
"*Run ¡ägrep¡ä PROGRAM to match EXPRESSION in FILES..." t)
(autoload (function igrep-find) "igrep"
"*Run ¡ägrep¡ä via ¡äfind¡ä..." t)
(autoload (function dired-do-igrep) "igrep"
"*Run ¡ägrep¡ä on the marked (or next prefix ARG) files." t)
(autoload (function dired-do-igrep-find) "igrep"
"*Run ¡ägrep¡ä via ¡äfind¡ä on the marked (or next prefix ARG) directories."
t)
(autoload (function grep) "igrep"
"*Run ¡ägrep¡ä PROGRAM to match EXPRESSION in FILES..." t)
(autoload (function egrep) "igrep" "*Run ¡äegrep¡ä..." t)
(autoload (function fgrep) "igrep" "*Run ¡äfgrep¡ä..." t)
(autoload (function agrep) "igrep" "*Run ¡äagrep¡ä..." t)
(autoload (function grep-find) "igrep" "*Run ¡ägrep¡ä via ¡äfind¡ä..." t)
(autoload (function egrep-find) "igrep" "*Run ¡äegrep¡ä via ¡äfind¡ä..." t)
(autoload (function fgrep-find) "igrep" "*Run ¡äfgrep¡ä via ¡äfind¡ä..." t)
(autoload (function agrep-find) "igrep" "*Run ¡äagrep¡ä via ¡äfind¡ä..." t)
(autoload (function dired-do-grep) "igrep"
"*Run ¡ägrep¡ä on the marked (or next prefix ARG) files." t)
(autoload (function dired-do-grep-find) "igrep"
"*Run ¡ägrep¡ä via ¡äfind¡ä on the marked (or next prefix ARG) directories."
t)


However, when I use the function fgrep or igrep,there is a message saying:
symbol's value as variable is void : grep-null-service.why?