What type of email address do you have? Have you tried to reset the password on a computer recently?
Another option to look at is that the account in question cannot be validated by BIS. You may still be able to access the email account via some other means but if the normal course for BIS to contact the email account is not working, it will fail and not validate. Is the account a webmail like yahoo or google or a personal work account? You can log into BIS at https://bis.na.blackberry.com/html?brand=vzw&locale=en view your 3 email accounts there and you have the option of trying to validate it there. You do not neccessarily need to put the password in to do this on BIS unless the password did change.
I doubt it changed though if all 3 accounts suddenly asked for validation.