Protected Content : password protect a set of pages

[Gederp]

Hi,
Thanks for this plugin.
I installed it on my server but I can reach the protected page.
I have verified the login/password : that's good.
I'm not using other plugins and I have tested on Firefox and IE.

I'd like to know what could I do : I tried to change login/pass and access file on directory, without effects.
What could we do to update it ?

Few more details : when I clic on my protected page, the popup shows asking login/password. Pressing ok close the popup and open another one. I can't access to my content.
What could I modify to use it ?

Thanks for your help.