[Mediawiki-l] Extension:Chemistry question

[John W. Foster]

I'm getting this error when I run Update.php on my site.

> myname at mysystem:/home/myname# php /home/myname/mediawiki-1.17.0/maintenance/update.php
> PHP Warning:  include(/home/frosty/mediawiki-1.17.0/extensions/Chemistry/ChemicalSources.alias.php): failed to open stream: No such file or directory in /home/myname/mediawiki-1.17.0/includes/LocalisationCache.php on line 411
> PHP Warning:  include(): Failed opening '/home/myname/mediawiki-1.17.0/extensions/Chemistry/ChemicalSources.alias.php' for inclusion (include_path='.:/usr/share/php:/usr/share/pear') in /home/myname/mediawiki-1.17.0/includes/LocalisationCache.php on line 411
> MediaWiki 1.17.0 Updater
> 

I am trying to install Extension:Chemistry & getting this error.
Any ideas on how to fix this? I have the required entries in LocalSettings.php

> require_once("$IP/extensions/Chemistry/ChemFunctions.php");
> 
> # (for the ChemFunctions tags)
> 
> require_once("$IP/extensions/Chemistry/SpecialChemicalsources.php");
> 
> # (for the Special:Chemicalsources page)