Scripting problem

Anyone know whats wrong with this script:

if (salvage_operation_occured) then
    call Sys_Get_List_Of_All_Players(player_list)
    set player_count := player_list.count()
    for index4 := 1 to player_count do
      set this_player := player_list.get(index4)
      call ship_list.clear()
      set ship_count := Sys_Get_List_Of_Space_Objects_Of_Type(5,ship_list,TRUE,FALSE,this_player)  
      set ship_count1 := ship_list.count()
   // Test Value Insert
      call Sys_Set_Event_Storage_Long(11,ship_count)
      call Sys_Set_Event_Storage_Long(12,ship_count1)

I've tried several options with the sys_get_space_object_of_type(), 5 is the constant for ship, the this_player cycles through the player IDs and ship_list should fill with the ID of all the player ships (it doesn't) and I should get a number count with the function (I don't), the boolean value does get a TRUE to execute the IF statement.
I check the obvious, I have two ships owned by player 1 but I get 0 in return. Is there something wrong with the function that I'm not aware of?[/code]