Someone must have updated your site to php7. The PowerCMS code will only work on php6 and below, so you will have to downgrade on your server. Your web hosting provider should be able to help with that.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.