Getting logged out from forums

[Tony Jose]

Hi friends,
I just started to use Tor. But i am not able to browse forums
properly. Everytime when i click any thread it says i am not logged in
and i have to retype username and password. this happens also when i
click the 'next page' or 'prev page' or any  link(in the thread)....

Is this a feature by design?? 
(BTW i am using netscape and cookies and javascript are enabled..)

thanks
tony.