Could not access network location %APPDATA%\.

Im getting this error message everytime I try to reinstall my itunes or uninstall my quicktime. This all started cause my itunes stopped working, whenever I would try to open my itunes it would pop up with that same message so i decided to uninstall it which it worked but then i couldnt install it again and since then i haven't been able to get it to work and everytime i try to install it i can't get it to work much less anything else i try to install. Also in the middle of typing this i just tried to install the Opera browser and it gave me this message. " Error 1606. Could not access network location %APPDATA%\. " So I am really lost to as why everything just stopped working cause everything was fine at first so any help with my problem would be greatly appreciated. Thanks.

I think some application might have corrupted your user's Application Data path (and most probably some other locations as well) security settings.

any idea how i can fix this problem?