[Koha] Login problem in Koha intranet

Hi, I've a new installation of Koha 2.2.9 in Windows XP. But when I login into Koha Intranet, everytime I choose any option it logs me out and login screen comes up. For example if i've choosen 'Parameter' option, I get the login screen again. then again after entering the username and password if I choose to 'Library Branch' I get the login screen again and after doing several logins the data is not getting stored in the database. I'm not understanding what went wrong. Can anyone help me in fixing this problem? Thanks in anticipation -- Nabonita