When being stopped at the Turkish side of the border Isa and Daniel should have crossed the Bulgarian check point already which should have required the missing Daniel's passport.
The movie starts with a total solar eclipse on July 7. Some hints (German Marks; the war in Yugoslavia) show that the story took place between 1991 and 2001. However, there were no solar eclipses on July 7 after 1880. The only total solar eclipse in 1991-2001 happened on July 11 1991 and was only visible in Western Hemisphere.
During the end of the film, Daniel, Juli, Isa and Melek pass the Fatih Sultan Mehmet Bridge (Second Bridge) from the European side to the Asian side just after Daniel and Juli are picked up by the others, but seconds later during the helicopter shot they are crossing from the Asian side to the European side on the Bosphorus Bridge (First Bridge).