I have been running McAfee security without a problem using Firefox; however, as soon as I updated to Firefox 4.0, I started getting this error and I have to click OK before Firefox opens.
Error: can't create mcafee plug-in object: TypeError:Components.classes[cid] is undefined
Any thoughts about how to fix it?? Thanks!
Please go to Add/remove programs (Windows XP) or Programs and Features (Windows Vista and 7) and select McAfee product and remove Site Advisor and restart the computer
Go to www.SiteAdvsior.com and click on Free Download button and re-install Site Advisor and let me know if that solved your issue or not. Best of luck