ok so i have the same problem as Fallingwater
i tried registering with yappari, it failed for the first time and asked me to wait for 57 minutes. after that i tried again, it asked me to try again after 24 hours.
Then i rebooted to NITDroid and registered with whatsapp and rebooted back to Maemo. I followed the steps given in the first post which lets me use whatsapp on NITDroid and Maemo. I entered my phone number and it failed again. This time it askes me to wait for 48 hours!! It just refuses to log in on Yappari. I have the latest version of Yappari installed.