[Plugin: Instapress] Settings not saving

Hello there,
I have just installed the latest version of instapress, but when I put in my username and password on the settings page, and try to save, it just returns a blank page.

I am on a multisite install, with not so many other plugins activated. Any ideas why this would happen?

Thx for the help!

http://ww.wp.xz.cn/extend/plugins/instapress/