Make sure that you have the deprecated Server Behaviors extension installed:
http://www.webassist.com/tutorials/Deprecated-Server-Behaviors-for-Dreamweaver-Creative-Cloud
The Screen Shot looks like the MySQLi extension did not completely install.
After installing the extension in the Extension Manager, when you open DW, it should launch the WebAssist installer. If the WA Installer does not open automatically, open a PHP page to force it to open.
Make sure that you restart DW after the WebAssist installer completes.