Invalid argument supplied for foreach()

Hello,

I have encountered a probelem while making a website. There are 3 error message
simple-job-board-applicants.php on line 56
simple-job-board-applicants.php on line 60
simple-job-board-applicants.php on line 72

The .php file is I have managed to find and in Bold is

if (in_array(‘jobapp_name’, $keys)):
echo get_post_meta($post->ID, ‘jobapp_name’, true);
endif;

if (in_array(‘resume’, $keys)):
?>
    <small>ID, ‘resume’, true); ?>” target=”_blank” ><?php echo __(‘Resume’, ‘simple-job-board’); ?></small>
<?php endif; ?>

</h3>
<table class=”widefat striped”>
<?php
do_action(‘sjb_applicants_details_start’);

foreach ($keys as $key):
if (substr($key, 0, 7) == ‘jobapp_’) {
echo ‘<tr><td>’ . ucwords( str_replace(‘_’, ‘ ‘, substr($key, 7))) . ‘</td><td>’ . get_post_meta($post->ID, $key, true) . ‘</td></tr>’;
}
endforeach;