I am being forced to learn corporate level networking management skills at an alarming rate for work....
I dont have all the answers, but most of my ideas are pretty sound, and this should be fixable at the user level... it is not really a website problem.
We have similar problems at work using our network machines with operating systems ranging from XP to vista and Windows 7, all with the most recent updates and service packs, when attempting to view various websites.
Generally, it is a security settings issue created by the users web browser.... a pop up window states something about viewing secure material (https) over a nonsecure (http) connection... there is a yes and a no tab for you to click
If you click yes, it shows only secure connection stuff... all else is small boxes with red X's in them. press no and you see it all, but it isnt a real secure connection. and there may be a check box saying always perform this action.
The bad thing is sometimes if you select the always perform this action box, it is near impossible to uncheck that box so you can view the material.
And it is a different fix for each web browser used(mozilla, firefox, internet explorer).
Quickest is to uninstall your web browser and reinstall it again (after restarting your computer).
I wish I could give you a for sure fix, but I havent had this problem here in a while.... and I cant really remember what I did to fix it.
It is different for each computer too.