Quick note to add that I also had this issue on: "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1b2pre) Gecko/20081027 Minefield/3.1b2pre" nightly Build 20081027034223
Disabling AVG safe search cured the problem.
Quick note to add that I also had this issue on:
"Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1b2pre) Gecko/20081027 Minefield/3.1b2pre" nightly Build 20081027034223
Disabling AVG safe search cured the problem.