Using just a Garland theme, we found that when typing into the autocomplete (on add-to-queue form) the displayed suggestions were aligned to the top of the form field, effectively hiding any values you typed.
This is not normal autocomplete behavior.
I traced it to a conflict between the '.display-inline' class (system.css) on the form field. So it's not specifically a nodequeue thing.
And I know this is D6, but somebody only just noticed it and started complaining.

Anyway, I made it go away with a quick hack looking like this

--- a/sites/all/modules/nodequeue/includes/nodequeue.admin.inc
+++ b/sites/all/modules/nodequeue/includes/nodequeue.admin.inc
@@ -806,7 +806,8 @@ function nodequeue_arrange_subqueue_form($form_state, $queue, $nodes, $subqueue)
     '#autocomplete_path' => 'nodequeue/autocomplete/'. $subqueue->sqid,
     '#maxlength' => 1024,
     '#default_value' => t('Enter the title of a node to add it to the queue'),
-    '#attributes' => array('class' => 'subqueue-add-nid'),
+    // Patched dman 2013-07 as the autocomplete was obscuring the field.
+    '#attributes' => array('class' => 'subqueue-add-nid', 'style' => 'display:block'),
   );

Not the cleanest, but I don't want to invest too much thinking into what looks like an old issue that's not going to get much attention.

Just FYI, as I spent some time searching here to see if anyone else had encountered it.