Cannot access the T3 template from template manager within Joomla 3.2.2

folks

I have loaded successfully the T3_blank template and the plugin.

I was able to configure and develop the template and was impressed.
However now, suddenly I cannot access the template.
If I go to Template Manager and clock on t3_blank I get a http 500 in IE or a blank screen in Chrome with the Url
http://demowebs.net/GKI/administrator/index.php?option=com_templates&view=style&layout=edit&id=9

We are using Joomla 3.2.2, php 5.2.36

Any ideas please?

Nigel