On October 16, 2009 Firefox team has added WPF plug-in to the plug-in blocklist effectively disabling all the XBAP WPF applications in Firefox. The block is due to recently discovered vulnerability. At this point it’s unclear for how long this block is going to be in effect.
amCharts for WPF demonstrations on this site utilize the above mentioned XBAP WPF technology and are therefore affected by this block. In case you can’t open the demonstrations in Firefox, you should try them with Internet Explorer.