That was what I thought!
Nog's text, that he reads from a PADD in "The Nagus", says that the Bajoran system has 14 planets, of which at least 2 are habitable -- Bajor itself, and Bajor VIII (established in "Past Prologue"). It says that Bajor has only three moons. But "Progress" establishes Jeraddo as the fifth moon, and "Image in the Sand" gives Derna as the fourth.