PAOK owes 40% of Gekas's contract. It was part of the Salpiggidis between Goumenos and Panathinaikos. As a result PAOK will receive around 300,000 Euro from Panathinaikos, although I believe Goumenos allready collected 50,000 under the table from Panathinaikos from that portionof the deal.
As a sidenote, Panathinaikos really screwed up with Gekas. Here they had a player, who is worth 3.5 million, and they will only get 400,000 for him.