HOW I SOLVED IT:
I had already gived up with this problem when I found a solution.
I uninstalled Internet Explorer 8, rebooted the PC,
At first the problem continued, but after about 5 minutes using the PC and opening folders,
then the Runtime error 216 DISSAPEARED FOREVER.
I´ve continued using Internet Explorer 6.
Still, I don´t know if the problem would return reinstalling Internet Explorer 8.
THAT´S THE WAY I SOLVED THIS HORRIBLE ERROR!
Resume 3 steps:
3)Use PC normally, in about 15 minutes Error will dissapear.
Remember: Error 216 doesn´t dissapers inmediatelly .