Unable to add Users

Unable to add Users

I just signed up with a brand new account on the free trial for the standard version of Zoho CRM.
I have then upgraded the subscription to 4 users.

Now I want to add the extra users but am unable to do so because Zohoh add user screen won't let me select a role for the new user. Therefore I am unable to add new users.

Any ideas?

This is urgent so we can start using the system.......