Paypal is currently experiencing delays in sending notification of payments to our processing systems (see http://www.paypaldeveloper.com/pdn/blog/article?blog.id=mts_updates&message.id=186#M186). As such there might be delays between when you have paid for Cashcow and when the registration email containing the license key is sent out.
Paypal expects this issue to be resolved within the next 12 hours.
I'm sorry for any inconvenience this may cause and I will post again here once this issue has been resolved.
Thanks.
Bao