=== modified file 'modules/simpletest/tests/taxonomy_test.info'
--- modules/simpletest/tests/taxonomy_test.info	2008-11-02 14:42:45 +0000
+++ modules/simpletest/tests/taxonomy_test.info	2009-01-10 10:32:40 +0000
@@ -6,4 +6,4 @@ version = VERSION
 core = 7.x
 files[] = taxonomy_test.module
 hidden[] = TRUE
-dependencies[] = Taxonomy
+dependencies[] = taxonomy

=== modified file 'modules/system/system.admin.inc'
--- modules/system/system.admin.inc	2009-01-09 16:19:55 +0000
+++ modules/system/system.admin.inc	2009-01-10 10:34:35 +0000
@@ -643,12 +643,15 @@ function system_modules($form_state = ar
     // Mark dependents disabled so user can not remove modules being depended on.
     $dependents = array();
     foreach ($module->info['dependents'] as $dependent) {
-      if ($files[$dependent]->status == 1) {
-        $extra['dependents'][] = t('@module (<span class="admin-enabled">enabled</span>)', array('@module' => $files[$dependent]->info['name']));
-        $extra['disabled'] = TRUE;
-      }
-      else {
-        $extra['dependents'][] = t('@module (<span class="admin-disabled">disabled</span>)', array('@module' => $files[$dependent]->info['name']));
+      // Hidden modules are unset already.
+      if (isset($files[$dependent])) {
+        if ($files[$dependent]->status == 1) {
+          $extra['dependents'][] = t('@module (<span class="admin-enabled">enabled</span>)', array('@module' => $files[$dependent]->info['name']));
+          $extra['disabled'] = TRUE;
+        }
+        else {
+          $extra['dependents'][] = t('@module (<span class="admin-disabled">disabled</span>)', array('@module' => $files[$dependent]->info['name']));
+        }
       }
     }
     $form['modules'][$module->info['package']][$filename] = _system_modules_build_row($module->info, $extra);