6.1.1) When I click the speaker icon to enable sounds, a message "Error! Unable to play sounds." appears. How can I fix it?

It means that your web browser is not configured properly to play sound files (wav). Unfortunately there is no universal way to play sounds in JavaScript applications which would work with all browsers, so it is required to install a plug-in (e.g. QuickTime) first.

Please visit the QuickTime download page to download and install the plug-in. When it is done, restart your web browser and the sound problem should be solved.

If this solution does not help, the easiest way to remove the error message is to disable sounds, either by clicking the speaker icon again or unchecking the corresponding option at Settings / Tables page. You can help us to improve the sound functionality if you file a bug report, containing your browser name, operating system and any other information that would specify the problem source.