C:\Users\Alex\Desktop\Servers\Samp\IBS\gamemodes\IBS.pwn(10721) : error 029: invalid expression, assumed zero
C:\Users\Alex\Desktop\Servers\Samp\IBS\gamemodes\IBS.pwn(10721) : warning 215: expression has no effect
C:\Users\Alex\Desktop\Servers\Samp\IBS\gamemodes\IBS.pwn(10721) : error 001: expected token: ";", but found "if"

else
    {
        GetVehiclePos(PlayerInfo[playerid][pVeh], vx, vy, vz);
        SetPlayerCheckpoint(playerid, vx, vy, vz, 2);
        SendClientMessage(playerid, COLOR_GREY, " A marker on your GPS showing where your vehicle is has been placed.");
    }
    else if(!strcmp(params, "sell", true, 8))//Line:10721
    {
        new playerb, modelid, vehicleid;
        if(!IsPlayerLoggedIn(playerb)) return SendClientMessage(playerid, COLOR_GREY, "Invalid player ID.");
        if(sscanf(params, "s[32]ui", params, playerb, input)) return SendClientMessage(playerid, USAGE, "[Usage]: /v sell [playerid] [price]");
        if(playerid == playerb) return SendClientMessage(playerid, COLOR_GREY, "You can't sell cars to yourself.");
        if(PlayerInfo[playerb][pVeh] && PlayerInfo[playerb][pVVeh] && PlayerInfo[playerb][pVVVeh]) return SendClientMessage(playerid, COLOR_GREY, "That player already owns two cars");
        if(PlayerInfo[playerb][pMoney] <= input) return SendClientMessage(playerid, COLOR_GREY, "That player does not have enough money.");
        new Float:X, Float:Y, Float:Z;
        modelid = GetVehicleModel(playerid);
        vehicleid = GetPlayerVehicleID(playerid);
        GetPlayerPos(playerb, X, Y, Z);
        if(PlayerInfo[playerb][vModel])
        {
            GiveDodMoney(playerb, -input);
            GiveDodMoney(playerid, input);
            PlayerInfo[playerid][pVVeh] = 0;
            PlayerInfo[playerid][vVC1] = 0;
            PlayerInfo[playerid][vVC2] = 0;
            PlayerInfo[playerb][pVVeh] = vehicleid;
            PlayerInfo[playerb][vVModel] = modelid;
            PlayerInfo[playerb][vVC1] = 0;
            PlayerInfo[playerb][vVC2] = 0;
            format(string, sizeof(string), "AdmWarn:%s %s has gifted %s a %s.", RPALN(playerid), RPN(playerid), RPN(playerb), RVN(GetVehicleModel(PlayerInfo[playerb][pVeh])));
            SendAdminMessage(COLOR_DARKRED, 1, string);
            return 1;
        }
        if(PlayerInfo[playerb][vModel] && PlayerInfo[playerb][vVModel])
        {
            GiveDodMoney(playerb, -input);
            GiveDodMoney(playerid, input);
            PlayerInfo[playerid][pVVVeh] = 0;
            PlayerInfo[playerid][vVVC1] = 0;
            PlayerInfo[playerid][vVVC2] = 0;
            PlayerInfo[playerb][pVVVeh] = vehicleid;
            PlayerInfo[playerb][vVVModel] = modelid;
            PlayerInfo[playerb][vVVC1] = 0;
            PlayerInfo[playerb][vVVC2] = 0;
            format(string, sizeof(string), "AdmWarn:%s %s has gifted %s a %s.", RPALN(playerid), RPN(playerid), RPN(playerb), RVN(GetVehicleModel(PlayerInfo[playerb][pVeh])));
            SendAdminMessage(COLOR_DARKRED, 1, string);
            return 1;
        }
        GiveDodMoney(playerb, -input);
        GiveDodMoney(playerid, input);
        PlayerInfo[playerid][pVeh] = 0;
        PlayerInfo[playerid][vC1] = 0;
        PlayerInfo[playerid][vC2] = 0;
        PlayerInfo[playerb][pVeh] = vehicleid;
        PlayerInfo[playerb][vModel] = modelid;
        PlayerInfo[playerb][vC1] = 0;
        PlayerInfo[playerb][vC2] = 0;
        format(string, sizeof(string), "AdmWarn:%s %s has gifted %s a %s.", RPALN(playerid), RPN(playerid), RPN(playerb), RVN(GetVehicleModel(PlayerInfo[playerb][pVeh])));
        SendAdminMessage(COLOR_DARKRED, 1, string);
        }
    }
    return 1;
}

if( ... )
{
// code
}
else if( ... )
{
// code
}
else
{
// code
}

else
{
// code
}
else if( ... )
{
// code
}