Problem setting up account

Hello,

I have a problem setting up an account on bitbucket. When I attempt to create an account (Team) and invite other people from my company I get this error:

https://www.evernote.com/shard/s14/sh/1e30252a-3b85-435e-8f1a-aab2ed053454/a4bd38d60dc92aa6e9a0e080aa0ec70a

I'm not sure: should I invite p.josiek@futuremind.com to bitbucket first somehow? Or does he have to be a registered user?

Regards,
Tomasz Koperski