Small thumbnails not showing

Hi there,
Thanks for the plugin. Everything works perfectly for my needs other than one thing. When I go to insert media to a post or page from the ‘media library’ tab then the small thumbnail that is normally visible for each image (prior to pressing the ‘show’ link) is not visible. When I deactivate the plugin it returns.

Any help with this would be a real help. Many thanks,
Joe

http://wordpress.org/extend/plugins/multiple-galleries/