You should be able to add as many connections as you want. I'm not sure why the connection isn't working, but it doesn't have anything to do with it being the second one. Maybe the IP address or credentials are wrong.
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.