I quote Balsamiq's position on this:

"There are too many technologies for a small company like ours to keep track of and export to, so we don't plan on adding export capabilities natively any time soon. Our strategy instead is to use an open, well-documented file format and work with partners to provide such features."

Sometimes it may take a while to receive the receipt and the license number since there could be random payment controls by Avangate or Paypal.
We have received complaints from GMail users as well: make sure to check your SPAM folder and search for a mail with the subject "Napkee Web/Flex/Web + Flex - License Number" from sales@napkee.com. If you cannot find it, please contact us and we will make sure that everything is fine.

Napkee 1.4.6 was published with a "too new" update framework inside which was affected by an Adobe Flex bug. If you see this window

when updating it means that your version of Napkee is affected too. Please use the install badge on the download page to upgrade to the latest and fixed version of Napkee that will re-enable the usual "Check for updates" process.

We will include here the answers to the questions we will receive more often.

In the meanwhile don't forget to check out the online help and to ask all the questions you want on the Napkee Get Satisfaction forums or any other contact method, we are here for you!