You can update your stream on the Account Info page. After you make the change, make sure you click Refresh on the Main tab in your App or post a new blog so the settings refresh for everyone.
Please make sure that you add the link to the Audio for the stream, not a link to a website or embedded music player. The app needs the actual audio stream to play. You can tell the difference because if you put that link in the browser online (i.e. Chrome, Firefox, etc...), the browser will open its own music player and play the audio. It won't load a webpage.
Account Info: https://www.blackvibes.com/members/personal.asp#radio