So you put WeatherUnderground.Weather in ACP's Weather Server ID? Check the Spelling.

ACP will start calling your server when you connect weather. One way to check it is to implement something in the SetupDialog() method. In ACP Preferences, Weather tab, click Setup Weather. This will call your SetupDialog() method (no parameters). The name of your server is intriguing!!! And you have error="true" which will pop up errors, but you can have debug="true" and install the Microsoft Script Debugger (in ProgFiles\ACP\ScriptING), or the full Visual Studio has a great script debugging facility. You'll need to check the "enter debugger" option in ACP Preferences, Debugging too. Now put a Stop statement (VBScript) or debugger; statement (JScript) and it will jump into the debugger at that point.