Changing portfilio item slug

Hi, I followed these instructions in order to change the portfoilio item slug http://blueowlcreative.com/support_wp/forums/topic/how-to-change-portfolios-slug-from-portfolio_item-to-something-else/

The issue now with the new plugin activated is that when I am creating a new portfolio item, the visual composer is not loading – the page in the admin dashboard looks like a blog post item with WYSIWYG – you can’t add rows etc.

Another thing is that when I switched back to the original portfolio plugin, a published portfolio item is showing 404 error when clicked form the grid.