Every now and then I'll be setting up a Drupal site, configuring modules and have things happen like the browse button for IMCE not showing up in the editor, or the Administration menu will be installed and configured but not appear (this also happens with Simplemenu) and 99.9% of the time this is because I forgot to dump the closing tag into my template.
Adding the closure tag to the bottom of my page.tpl.php file just about the closing body tag fixes the issue:
<?php print $closure; ?>