Administration Menu stopped working after installing new modules

I'm working on 2 different drupal websites and both have had this same problem. I installed the Administration Menu (admin_menu) module. It was working great. Then it disappeared. In both cases it *seems* to have disappeared after installing other modules.

In the first case it was Google Analytics, which I assumed was creating a javascript conflict. I disabled and uninstalled the Google Analytics module, but the Admin Menu didn't come back. I also tried "Wipe and rebuild" on the Admin Menu with no luck. I also tried disabling, uninstalling, and reinstalling Admin Menu, still with no luck.

In the second case, the same thing happened after I installed the "Filter By Node Type" module.

I have checked that my themes have print $closure at the end before the closing body tag.

Admin Menu seems to be running through it's functions like it should when it should, but it isn't getting any menu items. When it calls the function admin_menu_footer, it prints out the surrounding div but the admin_menu_tree_output is empty (line 149-151 of admin_menu.module).

Looking at the source code of the page shows the empty div at the bottom of the page and also shows in the header that it is including a link to /sites/all/modules/admin_menu/admin_menu.js?u.

At the top of the page where the Admin Menu should be, there is a space for it (the site is pushed down by 10 or 20 pixels) but there is no menu in the space.

I am using Drupal 6.10.

If anyone knows what the problem might be or what direction I can look in that I have not already looked, I would greatly appreciate it.