If you've reached the page shown below, it means you're currently locked out of your account for too many failed login attempts.
When your account is locked, you will not be able to log in - even with the correct password. This lock lasts about an hour and will then clear on its own.
If more than an hour has passed, or you're locked on your first attempt at logging in, please do the following:
Once you've confirmed you can log in at Twitter.com, you can individually re-enable the applications or widgets you'd like to use.