Can I have it on a subdomain and control content on main site to avoid conflict?

I am adding in the CMS to a friend's website using PowerCMS, and I noticed that when I have it loaded on the root of the main site, that there is a conflict (i think with the already existing javascripts on the site). I am now trying to set up the CMS on a subdomain and have it control the content on the main site, but this doesn't appear to be working? Can this be done?

The Site that I installed it on the root and having the error is: www.robert-hanley.saviodesigns.com (see attached image for error I get)

The site with the subdomain isL:
actor.php (I have a content area listed here, but it is not displaying the data.

The CMS is loaded on www.cms.saviographic.com

Many thanks!
~Chris

I actually just tried to log back into the subdomain CMS after loading the original site on the main folder, and now that same error is appearing...does it conflict with existing javascripts or something else?
Thanks for the help!

The screen shot you supplied shows the way the page would look if viewed outside of a web browser or without PHP installed. It appears the php parsing engine is not processing the php code on the page at all. This is a server configuration issue of some sort preventing any php from working from that directory.