view sort order issue

Hi - I have an issue here that has driven me batty... any help is very much appreciated.

http://www.centernetworks.com/jobs

Currently it shows jobs with the newest first. You can click on the other columns and it should sort by that column. But it does nothing - if you click city or state, it stays the same.

I've tried adding all of the fields in sort criteria, does nothing, tried it without, does nothing.

In the fields box, the only one that has sort option is the id field.

thanks.