As a measure of security, the system automatically blocks outdated plug-ins no matter the browser used (Safari, Mozilla, Opera, Chrome) and the easiest way to get rid of the problem in questions is to go to add-ons section of your favorite browser and perform a check for the latest installed plug-ins. All mentioned browsers have the ability to automatically update their installed plug-ins. In case your plug-ins are outdated, infected websites might try and profit based on “security holes” found in plug-ins and such your system could be infected in this case and that’s why the systems block the plug-ins and show that error.