Joomla 1.5 Moo 1.2.4 and IE9 bug fix

We did some testing today and discovered that mootools version 1.2.4 that comes with Joomla 1.5.22 upgrade plugin is not compatible with IE9. Some of you might see the javascript error that says

SCRIPT5022: DOM Exception: INVALID_CHARACTER_ERR (5)

It is visible in joomla admin and in frontend if you have any mootools based scripts including all our sliders, and Yj Mega Menu for Joomla 1.5

This post from Joomla org Joomla! • View topic - Mootools 1.2.4 and IE9 Bug advises how to  update the Joomla 1.5 core mootools upgrade plugin to version 1.2.5.  We have tested the advised mootools pack and it works.

Since this is Joomla core issue , we cannot perform the update until they do . So for the time being please download the file attached here and replace
SITE_ROOT/plugins/system/mtupgrade/mootools.js .

We have tested as much as possible and did not find any issues. Please reply to our forum post if you have any issues  with this file. Note that issue is visible only if Mootools upgrade plugin is on and you are using IE9 browser.