Yes, you can use the same email address in more than one account - you just can't "create" a new team account with an email that is already in the system.
This is by design, too many people would forget their password and create a new account rather than reset their password, this would cause all sorts of confusion.
The work around is to create a new account with a unique email address, once you have the new account you can set it to the same email as one used in another account.