Login issue

I am using wordpress 2.0 . When trying to login in both mozilla and internet explorer I cannot login. At first I will point to browser to http://192.168.0.40/wp-login.php . after hitting login the address bar will read http://192.168.0.40/wp-login.php/wp-admin/ . When I continue to hit the login bottun it will continue to append /wpadmin to the address add infenitium. If I change the address in the address bar to http://192.168.0.40/wp-admin/ it brings up the dashboard. This behavior has been repeated on several users machines. can this be fixxed? Please advise