As per ICAO guidelines, all accidents¹ and incidents² should be reported. Accidents should be investigated, whether incidents are is at the discretion of the agency collecting the reports.
Now whether, and how carefully, the investigation is done, depends on the country, but Greece is a functioning state and EU member, so chances of missing an accident there is pretty low.
Besides the web of the appropriate agency (already linked by Dave), there are two services that aggregate the reports, at least in the more serious categories:
They may not have everything, but the ASN should be fairly complete as far as accidents with any significant damage go, even including private and military flights. The AvHerald only concerns with commercial flights, but it also has a selection of incidents and the kind of “lesser” accidents like turbulence injuring some passengers or crew members.
In any case, something as severe as forced landing, be it ditching—which means landing on water—or off-field landing on ground, in a functioning state like Greece, would certainly make it to both, and a bunch of general news outlets too.
However, there are no commercial flight accidents for Greece in 2006 in ASN (the one listed accident is a fire-fighting aircraft), no accidents for Royal Jordanian Airlines in 2006 in ASN and search on AvHerald does not return anything either.
So it seems either your friend does not remember the place, airline or year well, or it was not such a big deal—perhaps the aircraft just diverted to some small airport due to a technical issue, which would be just an incident and wouldn't have to make these lists.
¹ An accident is any occurrence where somebody is killed or injured or there is substantial damage to the aircraft (excluding engines and landing gear) or other property.
² An incident is any occurrence where safety of operation might have been compromised (but didn't turn into an accident).