[Skimmer]

GivePlayerCash and ProxDetector aren't included in a_samp.inc
The server does not know this function and it gives you some Erorrs.
You should create stock for GivePlayerCash and for ProxDetector.

GivePlayerCash is there, to protect your server from Cheaters. There is already a function is called GivePlayerMoney. Cheaters can hack money, but they can't play with the Server variable.
I'm sure you have pMoney variable in your enum.

pawn Код:

stock GivePlayerCash(playerid, amount)
{
    if(amount >= 0) // amount is higher or is than 0
    {
        PlayerInfo[playerid][pMoney] += amount; // I'm not 100 per cent sure is your variable pMoney or pCash
    }
    else
    {
        PlayerInfo[playerid][pMoney] -= amount;
    }
}

If you want you can use direct GivePlayerMoney.

I hope i helped you @MouseBreaker