Sorry I do not know wher e zakinthos is but. You will need to go to greek embassy to provide you with a police check from your country of origin as this is also required. From Zakynthos I am not sure but here in london I went to the police station requested for a clearanceletter which is like a certificate they check on their computers and will show any crimes you had committed on a specified that you were in that country.
Let me know if this does not help.
Marita
