Prosites - Plugin could not be activated because it triggered a fatal error.

This shows at the top of the plugins screen when I try to activate the prosites plugin;

Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /home1/pathayso/public_html/atblogpages/wp-content/plugins/pro-sites/pro-sites-files/lib/ProSites/Module/Taxamo/lib/Taxamo/Swagger.php on line 172

Also I added the debug code to config file and go this;

[removed log as not relevant]