Fatal error installing AddThis

Hi,

I have a 2.7 blog working perfectly well with several plugins installed, but I get this error when trying to activate the AddThis Social Bookmarking Widget:

Parse error: parse error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /var/www/vhosts/xxxx.com/httpdocs/wp-content/plugins/addthis/addthis_social_widget.php on line 36

The installation itself completes normally and the plugin is there in my admin panel.

Can anyone suggest how to fix this please?

Thanks,
Ben