@ Alicanto

i had the same problem yesterday.
1.register your phone number on another phone or easier on pc via bluestack (android emulator) until the step where you have to enter the digit code ( 6 numbers)
- use bluestack, so you don't have to switch your sim card
2. You should get an SMS with the digit code
3. DON'T enter the digit code on the other phone/pc
4. start yappari and continue the registration on N900
5. enter the digit code you got before
6. yaparri should log in