What is my meeting password?
If you were invited to attend another person's meeting and are asked to enter a meeting password when join, then that means that the organizer who scheduled the session has password-protected the it for added security. This does not mean that you need to log in to a LogMeIn account; you just need to enter the password that the organizer set.
GoToMeeting does not store the passwords for password-protected meetings to ensure the security of your session, so the organizer should have provided it to you separately (most likely in the Invitation email). Please contact the organizer and ask them for the password if you can't find it in any prior communications.