Need help with nextgen-gallery

I have a very strange problem: my Nextgen-gallery plugin is disapeared. In my plugin-folder in webspace it is in the plugin folder, but in dashbord and plugins list it´s not there anymore and all my gallerys are gone. I can delete it and install it again, but if I do I have to load like 100 gallerys again and make all the discriptions and tags, will be so much work. Has anyone an idea what i can do?