Blank Page After Partial Upgrade

Good Morning:

Having a slight issue I am hitting a wall with. Have a friends site running great for a few years, I upgraded PHP on my server, and it pretty much broke the site. After some research I found,

http://www.zen-cart.com/showthread.php?140960-PHP-5-3-Support-for-v1-3-8-a

Which helped, I followed the steps, got the site almost all the way back up. However now I have an issue when a customer goes to add something to cart, "literally clicks the button" it throws up a blank page. I did some digging and it tells me to crawl the error logs server side, I see no logs in the log or cache folder.

http://bigeyecustomlures.com/shop/index.php?main_page=product_info&cPath=9&products_id=152&zenid=6a00445bf6cc920df304f1ae866a42fe

Once you click add this to cart it fails, can anyone help me please?

You should upgrade your site ASAP to at least Zen Cart 1.3.9h . Since 1.38 is old and has many security holes. Chances are upgrading will also resolve your other problem.

I figured it would come to that, I just did it. I triple checked all my work.

[22-Dec-2012 03:58:19 Europe/Moscow] PHP Warning: require(DIR_WS_TEMPLATEStemplate_default/common/html_header.php) [<a href='function.require'>function.require</a>]: failed to open stream: No such file or directory in /home/bigeye/public_html/doncart/index.php on line 43
[22-Dec-2012 03:58:19 Europe/Moscow] PHP Warning: require(DIR_WS_TEMPLATEStemplate_default/common/html_header.php) [<a href='function.require'>function.require</a>]: failed to open stream: No such file or directory in /home/bigeye/public_html/doncart/index.php on line 43
[22-Dec-2012 03:58:19 Europe/Moscow] PHP Fatal error: require() [<a href='function.require'>function.require</a>]: Failed opening required 'DIR_WS_TEMPLATEStemplate_default/common/html_header.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/bigeye/public_html/doncart/index.php on line 43

Is what I am getting in the debug error, I can log in fine to the admin, see products, etc. When I just try to view the site it is a blank page. Searching these forums for these errors now. If anyone can help that would be great!!!

The define for DIR_WS_TEMPLATES appears to be missing
Check your configure files to fix it.

Might have left off the trailing / in the config