Since you're using Views module version 2.12, I looked up that file in the repository viewer: http://drupalcode.org/project/views.git/blob/42fe4029ca7d7410f15933032a17e979bb0957c4:/handlers/views_handler_filter_in_operator.inc
Looks like line 206 should be: "$form['value']['#dependency'] = array($source => $this->operator_values(1));"
$form['value']['#dependency'] = array($source => $this->operator_values(1));
I'd try re-downloading the entire Views module. Maybe your copy of Views module got corrupted along the way?.