The issue in Dreamweaver seems to be a problem with your DW conection scripts. It could be a conflict with another extension you have installed. The correct course of action is probably to reinstall MySQLi Server Behaviors, which I can see you are trying to do.
The installer error in DMXZone extension manager appears to be a problem with the path. You can see the path it is trying to use is wrong in the error. I'd try installing the latest version of the DMXZone extension manager and see if that works. You might also try moving the extension into a different directory and/or browsing to it a different way if possible to see if you can get the extension manager to recognize the path properly.
Did this help? Tips are appreciated...
