[iorp]

Код:

stock PlayerIDs(string); // This value is not a string, it's integer 
stock PlayerIDs(const string[]); // This value is a string

I think you wanted to know that is given name player is connected or not, for that use this

Код:

stock bool:IsPlayerConnected(const string[])
{
    foreach(new i: Player)
    {
        new name[50];
        GetPlayerName(playerid, name[], sizeof name);
        if(!strcmp(name, string)) return true;
    }
    return false;
}