This is the same issue as #1708566: Error after changing to PHP 5.3 except it also breaks in version 7. My hosting company moved us all to PHP 5.3 last week and these errors started popping up:

Warning: intval() expects parameter 2 to be long, string given in views_calc_field_handler->render() (line 93 of /home2/woodford/public_html/sites/all/modules/views_calc/views_calc_field_handler.inc).

I get several hundred of these errors for a view with approximately 20 rows.

Comments

The php fix posted in #1708566: Error after changing to PHP 5.3 does not remedy the error in my view.

Removing the formatting from all of the fields defined in Views Calc temporarily fixes the problem.