Huub

I know one case where the audio bitrate was somehow changed . Jamulus requires 48 kHz. Maybe you can check this.

Private server: in Connection Setup window, the 'Server Address' box. Audio settings in "Settings" window.

Did you get the message "Do you want to allow downloads on “sourceforge.net”?" and allow sourceforge.net? You can change which websites can download files in Website Preferences. BTW I always use Firefox.