Emails sent to me for new user have empty Activation Key.

Hi,

I have a "vanilla" site with only some of your plugins. I have activated:
pro-site,
anti-splog,
Select Language At Signup,
Set Password on Multisite Blog Creation,
Remove Email Verification,
and Signup TOS.

When a new user sings up I receive an email with an empty Activation Key like:

The user "david" has submitted a manual payment request via the Pro Sites checkout form.

Level: 2 - Next
Period: Every 12 Months
User Email: david@ david.com
Activation Key:
Activation Link: http://domain.com/wp-activate.php?key=
Site Address: http://domain.com
Manage Site: http://domain.com/david/wp-admin/
Coupon Used:
Payment Amount: 100

Any clue?

Regards
Ans