Almost working - does everything but user continues logged out

After some other troubles, I finally managed (with the kind help of rick@pixeldirt) to make the module perform its whole cycle.

I can see the Facebook button.
When I press it it goes to facebook login page for me to login.
When I log-in at facebook it returns to my website.

But guess what? When it returns, the user is still logged out, and known to the system as guest.

I quite believe that it has something to do with correctly placing the code for working with PHP4. I believe maybe I haven't put it in the right place. Can someone help on that, or any other reason why it would not be receiving the parameters?