public OnPlayerFinishMission(playerid)
{
    SetPlayerScore(playerid, GetPlayerScore(playerid) + 3);
    new string[200];
    if (IsSmallAirCraftMission[playerid] == true) {
        new pname[24];
        new string[100];
        GetPlayerName(playerid,pname,24);
        format(string,sizeof(string), "%s completed %s in a dodo",pname,SmallAirCraftMissionRandom[MissionArrayID[playerid]][MissionName]);
        SendClientMessageToAll(COLOR_YELLOW,string);
    }
        else {
        new pname[24];
        new string[100];
        GetPlayerName(playerid,pname,24);
        format(string,sizeof(string), "%s completed %s in a Nevada",pname,CargoAirCraftMissionRandom[MissionArrayID[playerid]][MissionName]);
        SendClientMessageToAll(COLOR_YELLOW,string);
    }
    else {
        new pname[24];
        new string[100];
        GetPlayerName(playerid,pname,24);
        format(string,sizeof(string), "%s completed %s in a shamal",pname,PilotMissionRandom[MissionArrayID[playerid]][MissionName]);
        SendClientMessageToAll(COLOR_YELLOW,string);
    }
    return 1;
}

Error:
C:\Documents and Settings\Hayden Bruin\Desktop\UlitmateDM\gamemodes\SAP.pwn(2287) : error 029: invalid expression, assumed zero