http://127.0.0.1:44501/pl.html?START_LOG
Some people (including myself) using AdBlock observe that in each page they browse there’s a strange IFRAME loading the address given in the title of this post. Instead of uselessly googling after an explanation, you’d better open the HTML source files. You are not hijacked! At the bottom of each HTML file, Kerio Personal Firewall attaches this JavaScript file that is suposed to kill popups.
Of course, its name is misleading, Kerio does a bad job in advertising this feature, and Firefox does not need a supplemental popup killer. So if you’re browsing with Firefox, you might just disable Kerio popup blocker, from the Configuration window, tab "Web", "Ad block", unchecking "Block pop-up and pop-under windows".