Facebook Login Problems!

Hello,
I can't login to my Facebook.
I've tried on Firefox and Safari, to no avail.
Here's what happens:
I go on the www.facebook.com
I type in my email and password.
I hit 'login'.
As soon as I hit "login':
Safari says that it "couldn't establish a secure connection"
And Firefox just says that "there was an error in loading the page"
There's no loading, it just goes straight to these error pages.
Here's the weird thing:
it only has this problem on my iMac. My facebook logs in just fine on my friend's MacBook on the same network.
Can anyone help? This is very, very frustrating.

Thanks!