Internet Explorer issue

I have a problem when accessing an application via IE (this happens with multiple accounts accessing the site from multiple computers - only common point is IE). When you go to the URL (in this instance - http://www.zohocreator.com/mwbarker/koenigstuhl-run-2006/), all users have access to the registration page; this part works fine.

However, when you login as anybody that has access to the rest of the application, none of the tabs appear. In order to get the tabs to appear, you have to click on "My Home", then click on the Application. However, if you login to the site from Firefox, the tabs load up fine. I have been able to reproduce this every time I've tried it.