Invalid argument supplied for foreach() in /home/.../public_html/generator/pages/class.gping.inc.php on line 102

Error occurs when crawling. It seems to finish the crawl, however, doesn't write to the sitemap or index any pages.
Hi, i having the same issue, sitemap generator worked for 5 times in 5 weeks, now it give this error 
1 | 0 | 0.0 | 0:00:47 | 0:00:00 | 1 | 1,876.0 Kb | 0 | 0 | 1876
<h4>Completed</h4>Total pages indexed: 0
<br>Creating sitemaps...
<div id="percprog"></div>
 |  | 0.0 | 0:00:00 | 0:00:00 |  |  |  |  | 0
PHP Warning:  Invalid argument supplied for foreach() in /var/www/vhosts/xxxxxxx/httpdocs/sitemap/pages/class.gping.inc.php on line 102
 |  | 0.0 | 0:00:00 | 0:00:00 |  |  |  |  | 0
 |  | 0.0 | 0:00:00 | 0:00:00 |  |  |  |  | 0
<br>Sending email notification... |  | 0.0 | 0:00:00 | 0:00:00 |  |  |  |  | 0
<br />Done, redirecting to sitemap view page. <script> top.location = 'index.php?op=view' </script>