To set your password log in to one of the Engineering Suns. The first time you use your account the system will know you do not have a password and ask you to set one. You will be required to enter your password twice. You will not be able to see what you are typing. Your password must be at least 6 characters long and you must use at least one non-alphabetic character.
Numeric keypads are programmable.
Sometimes they are cursor keys. You can't see which characters are actually being entered when you are entering your password, so stick with the numbers on the top row of keys. Usernames are assigned in a manner that will allow effective user account management by the system administrator. The usual cause for this behavior is that you have exceeded your disk qouta and are not being allowed to log in for that reason. When you log in from the command line you will be given quota information.