Simple tree menu don't work properly in IE6 using includes?

[Windwill]

1) Script Title: Simple Tree

2) Script URL (on DD): http://www.dynamicdrive.com/dynamicindex1/navigate1.htm

3) Describe problem: I'm working on a site and I've used the simple tree menu, but all of a sudden the submenus won't stay open in IE6. The just revert back to their subtracted state when I click on a submenu. I think it was working before, but i'm not sure anymore. I saw that another user had the same problem, but that he had some sort of conflict with another program. I don't, at least I don't think so. I'm using include files on a coldfusion server. I't works fine on FireFox and IE7 but not IE6 (like sooo many other things). Anyone had the same problem but managed to solve it?

[Windwill]

Oh, I saw that i forgot to add my own url:
http://www.hittastilen.se/hs_linda/index_ny.cfm

Anyone who can help me? Can it be a CSS-problem or is it a cookieproblem?