I don't really expect an answer here, but thought I'd ask just in case.
I have a MODx site at LP where the Mootools JS that expands a tree node just quit working. The problem appears in several browsers.
The site hasn't changed and, so far, no one in the MODx community has the same problem except one person who also has a site at Lunarpages. My MODx sites at other servers don't have the problem.
I know JS is not a server-side process so this question doesn't make much sense, but has anything changed at LP lately that could cause this?
"View Source" to make sure the js is being called in the page. If you have FireBug, use it to see what's going on. You could have a permissions problem on the js file. Make sure it's 644.