Feedwordpress Problem

Hi all,
sorry for my bad english but i’m italian :D… I have a problem with this plugin: i put the address of rss feeds that i want to subscribe, i click update and it’s all ok.
But i can’t do that automatically! i activate the option but it doesn’t work for me!
If i click manual update a message tells me that he can’t found new post.. But there are new post!

Thanks a lot!