Plugin not working on some pages!

Hello!
This plugin is awesome but it seems like there’s a problem with some pages of my template.
You can see it here
http://www.piccololab.it/download/
>> plugin working perfectly (single page)

http://www.piccololab.it/photograph/true-artisans/
>> plugin not working (photograph page)

http://www.piccololab.it/blog/
>> plugin not working (blog page)

Also, it messed up with the original theme settings and even if I delete/deactivate it, it won’t let the theme get back to its original background.

Please help me fix it, I’d love to either use the plugin fully or not use it, but either way being able to control it.

Thanks

Alessandra

http://ww.wp.xz.cn/plugins/background-manager/