There is a bug in the Gallery module for embedding Gallery2 in Drupal.

When you install the Gallery module, you need to set the "gallery_embed_uri" to the location of the url of your main Drupal handler. (example: "/blog/index.php?q=gallery") If you change the url of your blog, while there appears to be a way to modify the gallery_embed_uri from the administration menus, it does not take. All links from Gallery2 items are to the wrong addresses.

In my case, while my main blog is in /blog/, I had a temporary location of /test1/ while I upgraded drupal and installed Gallery2. Once I was happy with the installation, I moved it to /blog/. Gallery2 continued to point to /test1/ no matter what configuration options I changed.

In the end, to fix the gallery_embed_uri, I had to modify the field in the Drupal database table "variable". Once I made the change in the database, Gallery2 started working perfectly.

Note: xmlsitemap uses the same gallery_embed_uri variable. Until gallery_embed_uri was fixed, all my Gallery2 items in my site maps were bad.