Please help !! vista settings

Hi everyone,
I have a new laptop with vista home premium, i download and installed bitcomet but when i push the button to log in is jumping to sing up, i write the user name and password ( more then 6 character each ) and i got the red message: password length should be whitin 6-20 character. i see the sing up button in a blue rectangle, so may be is the vista security settings but i don`t know how to figure out. PLEEEEASSSE HEEEELP ME !!!!
Also for yahoo messenger the same, i mean i check it to remember my username and password but after the program statrting if i don`t press the signin button very quick appear again the blue rectangle round to the button and password is gone.
Please help. Thank you.