Trying to remove sidebar from some pages

I tried your plugin to remove the sidebar from some pages on my site, it does work to a certain point.. but leaves a blank space instead of letting the page show full width, it was recommended by the theme provider and in some tutorials.. but have not been able to make it work as intended.. any suggestions? or am I using the plugin incorrectly.. thanks

The page I need help with: [log in to see the link]