youYou probably missed to configuremis-configured some of you ads right. GPT stands for Google"Google Publisher TagTag".
thereThere are some fallback tags that are marked up like this:
<script type="text/javascript" src="[GPT_URL]"></script>
ifIf you missforgot to fill out the [GPT_URL][GPT_URL]
, a browser thinks its a relative urlURL and so you get your missing urlsURLs.