Installation problem

Hi
I am using fresh installation without any other plugin with Twenty fifteen theme and I get this error message:
Parse error: syntax error, unexpected ‘class’ (T_CLASS), expecting identifier (T_STRING) or variable (T_VARIABLE) or ‘{‘ or ‘$’ in /home/gj/public_html/stp.com/wp-content/plugins/customer-area/src/php/core-addons/post-owner/helpers/post-owner-ajax-helper.class.php on line 63

Could you help please?

Thank you