AKO account and Safari

I have a AKO account with the Army and everytime I try to open the website I get told that Safari does not trust the cerificates. I have tried every avenue including setting "allways trust the certificates" regarding the website. Does anybody have the same problem and is so please let me know what to do.

I have the same problem regarding Mail.

I need help.

Thanks...

MackBook Pro Mac OS X (10.4.8)