I use an extension called FishPig with my Magento ecommerce store. This intergrates my WordPress in to my web site.
When I use the NextGen Plugin when I try to loo at the gallery in my post I just see [nggallery id=1] and not the gallery
Not sure if this is relevant but when I check plug in I get
Check theme compatibility
Missing the call to wp_head() in your theme, contact the theme author