doubt regarding registration of gre

hello i do not have a surname and i m not able to register at the ets site please help me for the solution.

will it be possible to register without the surname as my surname is not mentioned in any of my certificates and in my passport also.

Well, you should have an intial right ? Thats your Surname. What does your passport say in Last name or Surname field ?

its left blank in d section of surname in the passport.