redirect to login page

[SCW]

running v 1.3.2.3

There are 2 admins. Me - located in the U.S. and the other located in China.

I can log in and navigate the admin area just fine. But the admin in China is
having difficulties. He can log into the admin, but the moment he clicks on any
of the navigation tabs - he is redirected to login again. I asked him to clear browser
cache and make sure cookies were enabled. This did not help. One other thing:
initially, he was able to navigate, but for some reason, something changed.

Any ideas what could be causing this?

Thanks!