centre column for some people is at the bottom of the 2 side bars

Most people looking at this website see the two side bars and the blog entries in the middle.

For some people they see the 2 side bars and nothing in the middle. If you scroll down you will find the blog entries where the 2 side bars finish.

We are trying to see what we can do to fix the problem from our end. One person has told us that it could be the browser set up on the computers that have the info below the 2 side bars.