Fatal Error Upon Activation

Hi,

I'm getting the following error when trying to activate the WHMCS WP Integration plugin:

Plugin could not be activated because it triggered a fatal error.
Parse error: syntax error, unexpected T_FUNCTION in /home/webbrief/public_html/wp-content/plugins/whmcs-wordpresss-integration/whmcs-integration.php on line 811

Any help will be much appreciated.