Thread:Project:Support desk/Error while installing MediaWiki

I am trying to install media wiki in my server that has Red hat Linux ver. 6.

For this I have downloaded media-wiki.

After downloading and untaring, I renamed media-wiki directory to aps and kept it at: /var/www/htmlwiki/aps/ directory. Then, Google Chrome browser, I did:

http://14.139.223.112/wiki/aps/mw-config/index.php

It said: Fatal error: Class 'DOMDocument' not found in /var/www/html/wiki/aps/includes/cache/LocalisationCache.php on line 587

I found a solution in the media-wiki manual and tried:

yum install php-xml

That said:

Error Downloading Packages: php-xml-5.3.3-3.el6_1.3.x86_64: failure: Packages/php-xml-5.3.3-3.el6_1.3.x86_64.rpm from server: [Errno 256] No more mirrors to try.

What should I do next to install it correctly?