We ran into an error on the ext-all.js. It gives us an error stating: 'invalid procedure call or argument'

I've debugged the problem and it turns out that on line 26 of ext-all.js there is a method:
Code:
Ext.util.CSS=function(){var D=null;var C=document;var B=/(-[a-z])/gi;var A=function(E,F){return F.charAt(1).toUpperCase()};return{createStyleSheet:function(G,J){var F;var E=C.getElementsByTagName("head")[0];var I=C.createElement("style");I.setAttribute("type","text/css");if(J){I.setAttribute("id",J)}if(Ext.isIE){E.appendChild(I);F=I.styleSheet;F.cssText=G}else{try{I.appendChild(C.createTextNode(G))}catch(H){I.cssText=G}E.appendChild(I);F=I.styleSheet?I.styleSheet:(I.sheet||C.styleSheets[C.styleSheets.length-1])}this.cacheStyleSheet(F);return F}
For some reason F.cssText=G assignment is unable to be preformed. As if F.cssText was a private attribute. Any thoughts?