[arvifilter]

This error means that you have not made the "IsInvalidSkin"
You can make it like this:

Код:

//At the top of the script
new validskin[MAX_PLAYERS];
//public OnPlayerSpawn
if(GetPlayerSkin(playerid) == "invalidskinid")
{
    validskin[playerid] = 0;
}
else
{
    validskin[playerid] = 1;
}
//then where you need to check if the skin is valid
if(validskin[playerid] == 1)//it is valid
//or
if(validskin[playerid] == 0)