Hi emmajyu,

You should check in the lines of code that instantiate and then configure the connInfo object, something similar to this
Code:
            ConnectionInfo connInfo= new ConnectionInfo();
            connInfo.PushServerUrl= "http://" + pushServerHost + ":" + pushServerPort;
            connInfo.Adapter= "DEMO";
Please look for the server to which you are connecting, for example if you're hitting your local instance of Lightstreamer. And then check whether the server to which you are connected has succesfully deployed the Adapter Set concerned.

In fact, the exception "Requested Adapter Set not available" refers precisely to the fact that the Adapter Set configured by connInfo.Adapter = "XXXX" is not deployed on the server to which you are connected.

If you are connecting to a local instance of Lighstreamer a way to check which are the Adpaters successfully loaded is to look in the server log file where the "init" logger lists the loaded Adapters and reports any problems.

Please note that I have removed the thread in the ".Net Adapter API" forum considering it identical to this one.