Itunes comes with a whole bunch of adware stuff
Be carefull what you install during the installation.
Try to uninstall the program. Then install it again and read carefully what you install xtra ( if you want something xtra). I usually don't install the xtra's.

Maybe the add's which you could have installed can't be displayed because of the addblockers
maybe that conflicts with it.
Not sure but it could.

good luck with it.

-phunction