Install MultiUpload Extension in MediaWiki

I am trying to install "MultiUpload" mediawiki extension. I followed the installation instructions and added below code to my mediawiki "LocalSetting.php" file require_once("/var/lib/mediawiki/extensions/MultiUpload/MultiUpload.php"); but when I tried to verify the installation by go to the webpage http://myserverIP/wiki/index.php/Special:Version It gave me "http error 500". However I have successfully installed "FCKeditor" extension by using the below command and it went on very well: sudo apt-get install mediawiki-extensions sudo mwenext ParserFunctions.php My Apache error log shows: [Tue Mar 20 13:40:18 2012] [error] [client 172.29.35.61] PHP Warning: require_once(/var/lib/mediawiki/extensions/MultiUpload/MultiUpload.php): failed to open stream: No such file or directory in /etc/mediawiki/LocalSettings.php on line 142 [Tue Mar 20 13:40:18 2012] [error] [client 172.29.35.61] PHP Fatal error: require_once(): Failed opening required '/var/lib/mediawiki/extensions/MultiUpload/MultiUpload.php' (include_path='/var/lib/mediawiki:/var/lib/mediawiki/includes:/var/lib/mediawiki/languages:.:/usr/share/php:/usr/share/pear') in /etc/mediawiki/LocalSettings.php on line 142 [Tue Mar 20 13:40:19 2012] [error] [client 172.29.35.61] PHP Warning: require_once(/var/lib/mediawiki/extensions/MultiUpload/MultiUpload.php): failed to open stream: No such file or directory in /etc/mediawiki/LocalSettings.php on line 142 [Tue Mar 20 13:40:19 2012] [error] [client 172.29.35.61] PHP Fatal error: require_once(): Failed opening required '/var/lib/mediawiki/extensions/MultiUpload/MultiUpload.php' (include_path='/var/lib/mediawiki:/var/lib/mediawiki/includes:/var/lib/mediawiki/languages:.:/usr/share/php:/usr/share/pear') in /etc/mediawiki/LocalSettings.php on line 142 My "MultiUpload" directory shows: total 112 drwxrwxr-x 2 2010 500 4096 2009-06-10 15:57 . drwxr-xr-x 3 root root 4096 2012-03-20 13:38 .. -rw-rw-r-- 1 2010 500 788 2009-06-10 15:57 multiupload.js -rw-rw-r-- 1 2010 500 1100 2009-06-10 15:57 README -rw-rw-r-- 1 2010 500 2942 2009-06-10 15:57 SpecialMultipleUpload.alias.php -rw-rw-r-- 1 2010 500 13314 2009-06-10 15:57 SpecialMultipleUpload.body.php -rw-rw-r-- 1 2010 500 70689 2009-06-10 15:57 SpecialMultipleUpload.i18n.php -rw-rw-r-- 1 2010 500 3188 2009-06-10 15:57 SpecialMultipleUpload.php May I know how to troubleshoot this error and get this extension working on my mediawiki? I am using Ubuntu11.04, MediaWiki 1.15.5-3.