Network activation error on Pro Sites

I get an error when activating the Pro Sites plugin. Here it is:

Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM in /home1/youpickp/public_html/wp-content/plugins/pro-sites/pro-sites-files/lib/ProSites/Module/Taxamo/lib/Taxamo/Swagger.php on line 185

How can we solve this? Another unrelated question is on Blog Templates: how can I set it up so that new sites being created will get a copy of a certain blog template?