Thread:Extension talk:MobileFrontend/Doesn't work in MediaWIki 1.19

I downloaded the "mediawiki-extensions-MobileFrontend-REL1_19", then I install it to my Wiki's /extensions, also add

require_once "$IP/extensions/MobileFrontend/MobileFrontend.php"; $wgMFAutodetectMobileView = true;

to my LocalSettings.php

when I open my wiki, I got:

Warning: require_once(/[my path]/extensions/MobileFrontend/library/WURFL/Application.php) [function.require-once]: failed to open stream: No such file or directory in [my path]/extensions/MobileFrontend/MobileFrontend.php on line 27

then I go to check my extensions/MobileFrontend, I can't find "/library/WURFL/Application.php", also I check MobileFrontend.php line 27, there just "require_once( WURFL_DIR . 'Application.php' ); "

well, I don't understand how to fix it.