[Plugin: Polylang] Static pages "not found"

Hi everybody,
forgive my English please!
I have some problems with Polylang: I installed this plugin and it worked well (love it!). Then I had to deactivate it. (Here the wordpress version was 3.3.1)
I removed some plugins and installed Woocommerce, upgraded wordpress to 3.3.2, then I activated polylang with the same settings: but when I try to open a page, it shows “Not found”. Only home page works well (it is a static page).
So I uninstalled the plugin, then installed it again, but the problem is not solved.
I am using a child theme of Twenty Ten: in my local wordpress the plugin works well also within the child theme.
Thanks.