If you already have an account and you have NOT yet set a password you will need to set one:
Alternatively, if you have the original device your account was created on you may use the following instructions:
Launch Draw Something 2 on the old device where you created the account.
Tap on the "Me" button
Then on the "Edit Profile" button
Choose the Zynga Live Name option and set your new Password
Tap "Save"
Launch Draw Something 2 on your new device and login with your email and newly set password