So, I want to create my friend a profile on my game, but I can't seem to get it to work. I cannot really explain what's going on, but try to help me.

Erm, so we need to guess what's going wrong? Is it so hard to put that one more sentence, with even basic details like "creating window doesn't appear"?

Okay, trying to explain.
1. Click "Create a new profile"
2. "Create a new account"
3. Enter a login, password, etc. (OK)
4. Choose your zone, enter an email address... (OK)
5. The EULA thingie.
6. Enter your key *enters key*
7. Error: Account creation failed. This game key is already used. Retry?

So does this mean we can only have multiple accounts in one game if we buy new keys?

Yes, I believe so.

For hotseat and such, you can create the account while starting up the match.

-_-