Well Paul,
It makes me suspect a credentials (password etc.) problem or possibly a sound card problem.
As a test, try the free version of Rocket Broadcaster or B.U.T.T. and see if the same problem occurs with the same credentials on your Optiplex.
Rocket has a nice test function where it shows you where it fails (and the paid version is well worth it as it allows processing).
Paul Harriman
Am running latest version of Playit Live and trying to stream through Shoutcastv2. Have set up streaming plugin but I can't get on air to stream, it says logged in but it does not stream. Comes up saying "active" and logged in, but at top right hand side of screen where Stop/Start button is, it keeps flickering between off and on air. I am using a Dell Optiplex 9020 connected to net via ethernet cable. Strange thing is, my laptop connects straight away to shoutcast using wifi? Got me stuffed, any help would be appreciated,
Cheers,
Paul