In post ads is generating thousands of error messages

Hello,
Why is this plug-in generating thousands of these error messages:

[04-May-2016 08:20:51 UTC] PHP Strict Standards: Redefining already defined constructor for class Wdca_PublicPages in /home/uworldsus/public_html/hotel/globalhoteldirectoryinfo/wp-content/plugins/custom-ads/lib/class_wdca_public_pages.php on line 13
[04-May-2016 08:20:51 UTC] PHP Strict Standards: Non-static method Wdca_PublicPages::serve() should not be called statically in /home/uworldsus/public_html/hotel/globalhoteldirectoryinfo/wp-content/plugins/custom-ads/custom-ads.php on line 79

Thanks