Validation PMDG 747-400 FSX

Hi,Forgive me if this has been posted earlier but I could'nt find anything.I bought and downloaded PMDG boeing 747-400 normal and cargo.When I get to the validation I get a message that the installer could not validate my data probibly because of my firewall. When I turned off my firewall but I still get the same messages.Now I cannot install the thing an I feel I am out of options. Has anyone had similar expiriences and how did they solve it. I spend whole yesterday searching on the internet but very little people have the same problems.Regards,Appie