Probably caused by a Firefox extension which is related to "air miles" tracking. Disable that extension until that server certificate error is fixed.

http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+themes

http://www.flyertalk.com/forum/united-mileage-plus-consolidated/1262830-anyone-else-seeing-ssl-error-xml-freecause-com-caused-mileage-plus-toolbar.html

Looks like this error can be caused by any number of third party toolbars.

For me, the offending toolbar was the "gamers unite snagbar" -- which I haven't used for about a year so I uninstalled it.

To uninstall the offending toolbar you will first need to change your computer's date to a date before the expiration of the certificate showing on your error message.

Click on "cancel" on the error message.

Then, go under "tools" and choose Add-Ons>>Extensions and try uninstalling whichever toolbar you think may be causing the problem. Restart Firefox. Hopefully you will no longer have the error message.

Then, of course, change the date back to the correct date.

you suggest to locate the extension and then disable.. it's already showing as disabled. So I sure as heck hope it's gone.. it's like a virus problem that will not go away.. and it's intrusive and frustrating and criminal

I have been hunting through the certificates to no avail to delete this bastard!

Not to mention the fact that firefox has been crashing constantly since 6.02 doesn't help me gain any ground if it keeps crashing while I am trying to figure it out.

I found that if you keep hitting the close button eventually it stops for about 5 min long enough to pull up the tools security and view certs window. also opening another firefox window helps for a bit

i found a reference to freecause being associated with yahoo toolbar. I don't have that installed

I had this problem too...I also had the Gamers Unite snagbar. Changing to a past date, uninstalling the snag bar, then updating to the correct date solved the problem. Thanks grinchers!

Got it, thanks, my offender was the MyYearbook toolbar which i think used yahoo

After finding it was disabled .. it intruded upon my computer again.. had to click about 10 times to close it! what is the solution? why is this invading my privacy and interfering with everything? This is unacceptable and corrupt! please eliminate this crap!

mine was an AAdvantage Miles toolbar that used yahoo.

Can anybody help? After removing the bad add-on for this stupid, repetitive & annoying error and restarting my pc --- how to date back to the correct date as you suggested? Thanks.

This is starting to SUCK! I love Firefox, but not this stupid error. I'm about to switch to Chrome! I set my calendar back about two weeks, but it popped up again when I tried to play Words with Friends through Facebook. (Of course, I wouldn't be surprised if this also has to do with they changes THEY made.) Maybe I'll set my calendar back further....

I tried changing the date to a week prior. Still got the message. I uninstalled Firefox and reinstalled it and so far so good.