Thanks for all your replies, I am currently running google Chrome 8.0.552.237, but I am having problem to load the designer, it only works in Safari so far. With google Chrome, it shows the the designer, but with a message box saying "Intalio Process Designer Please wait while loading,..." then it stops there, and I could not use the designer.
I am going to try the Google Chrome Frame suggestion, but I am not sure if it will work if it does not work with google chrome.
BTW, I am using JBPM5 web designer.
Thanks again!