There is definitely a bug in NextGEN Gallery 2.0.66.29. Here’s a patch:
--- a/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/admin/functions.php
+++ b/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/admin/functions.php
@@ -37,7 +37,8 @@
$txt = '';
$galleryObj = new stdClass;
- $galleryObj->path = '';
+# $galleryObj->path = '';
+ global $ngg; $galleryObj->path = $ngg->options['gallerypath'];
$nggRoot = $storage->get_gallery_abspath($galleryObj);
// No gallery name ?
