diff --git a/taxonomy_access_fix.install b/taxonomy_access_fix.install
new file mode 100644
index 0000000..5a9d6c8
--- /dev/null
+++ b/taxonomy_access_fix.install
@@ -0,0 +1,41 @@
+<?php
+/**
+ * @file
+ */
+
+/**
+ * Updates existing role permissions stored in the database, changing vid to 
+ * machine name for correct usage.
+ */
+function taxonomy_access_fix_update_7101() {
+  $permissions = array();
+  $vocabulary_ids = array();
+
+  $query = db_select('role_permission', 'rp')
+    ->fields('rp')
+    ->condition('module', 'taxonomy_access_fix', '=')
+    ->execute();
+  while ($permission = $query->fetchObject()) {
+    $permissions[] = $permission;
+    $vocabulary_ids[] = (int) substr($permission->permission, strlen('add terms in '), strlen($permission->permission));
+  }
+
+  if (!empty($permissions)) {
+    $vocabularies = taxonomy_vocabulary_load_multiple($vocabulary_ids);
+    if (empty($vocabularies)) {
+      return;
+    }
+
+    foreach ($permissions as $k => $permission) {
+      $vocabulary = $vocabularies[$vocabulary_ids[$k]];
+      db_update('role_permission')
+        ->fields(array(
+            'permission' => 'add terms in ' . $vocabulary->machine_name,
+          ))
+        ->condition('rid', $permission->rid, '=')
+        ->condition('permission', $permission->permission, '=')
+        ->condition('module', 'taxonomy_access_fix', '=')
+        ->execute();
+    }
+  }
+}
diff --git a/taxonomy_access_fix.module b/taxonomy_access_fix.module
index 36acf93..cc90d79 100644
--- a/taxonomy_access_fix.module
+++ b/taxonomy_access_fix.module
@@ -56,7 +56,7 @@ function taxonomy_access_fix_permission() {
   $permissions = array();
 
   foreach (taxonomy_get_vocabularies() as $vid => $vocabulary) {
-    $permissions['add terms in ' . $vid] = array(
+    $permissions['add terms in ' . $vocabulary->machine_name] = array(
       'title' => t('Add terms in %vocabulary', array('%vocabulary' => $vocabulary->name)),
     );
   }
@@ -111,23 +111,21 @@ function taxonomy_access_fix_access($op, $vocabulary = NULL) {
     case 'index':
       // Only if they have >= 1 vocabulary access.
       foreach (taxonomy_get_vocabularies() as $vid => $vocabulary) {
-        if (user_access('edit terms in ' . $vid) || user_access('delete terms in ' . $vid) || user_access('add terms in ' . $vid)) {
+        if (user_access('edit terms in ' . $vocabulary->machine_name) || user_access('delete terms in ' . $vocabulary->machine_name) || user_access('add terms in ' . $vocabulary->machine_name)) {
           return TRUE;
         }
       }
       break;
     case 'list terms':
       if ($vocabulary) {
-        $vid = $vocabulary->vid;
-        if (user_access('edit terms in ' . $vid) || user_access('delete terms in ' . $vid) || user_access('add terms in ' . $vid)) {
+        if (user_access('edit terms in ' . $vocabulary->machine_name) || user_access('delete terms in ' . $vocabulary->machine_name) || user_access('add terms in ' . $vocabulary->machine_name)) {
           return TRUE;
         }
       }
       break;
     case 'add terms':
       if ($vocabulary) {
-        $vid = $vocabulary->vid;
-        if (user_access('add terms in ' . $vid)) {
+        if (user_access('add terms in ' . $vocabulary->machine_name)) {
           return TRUE;
         }
       }