OK, code seems fine. Here's a couple of other things to check:

Have you changed any of the categories so that 'isSub' equals YES? If not, you'll need to change them.

Have you done a 'build' since you changed the code? If not, do one as it'll re-write your category pages using the updated version of the templates with the new 'isSub' details in (that may be the problem as I forgot to mention it in my original post - sorry - I've updated that thread with this addition!).

If you do a re-build and its still not working, maybe we should take it to email and work from there.

All the best
Shaun
webmaster@qango.com