PHP Problem- login problems

[system]

I have a problem. I added a login and registration page. Every time a user registers, everying is fine. But when the user uses his/her registered username and password to login in, the error message: “You did not fill in a required field.” My database as three fields, ID, User, and password. HELP.

Thanks

[lothop]

Make sure your field names and the POST or GET variables match.
If you give us your code we can look over it.