Cufon-yui.js script prevents accented vowels (ã ,ó, í à á ) to be renderized

I am customizing a site template and noticed that accented vowels (ã , é, ó, í ) are not renderized by the browsers.
The culprit is cufon-yui.js , if commented the problem is solved.
Useless to use special ASCII html character codes like Í Í , etc.
How to solve this ? simply do away with this script ?
Please help me out friends.
Thanks