Well, this file may help you. Locate your existing Mootools file in your RT/Yoo Theme template and rename it to xxxxxxxx2.js or whatever name it may have. Once you have done this, rename the file that is attached to this post as the name of the original mootools js file. Then simply upload it via FTP.
This may/may not work. If it works, great let me and the community know. If not, sorry just delete the newly installed file and replace it with your original. Remember to rename it though..
Thanks,
James