Just installed and tested under X.5.6 on an Intel Mac and it works great! The spacers are very handy!

If there was one thing I'd like to see added is to have the option of adding in line dividers instead of spaces. Basically so that there would be less space used on the dock for dividing things up.

Another useful bit would be allowing for changing the font size for the display name for icons in the dock. I'm sure those of us with good eye sight would luv to make that text smaller.

As it is, though, it is still a great little utility! By the way, if you're looking to divide the dock under X.5.6, this is the only utility that will do that.