[YoYo123]

Try this

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    dcmd(register,8,cmdtext);
    
    new file[256],n[MAX_PLAYER_NAME];
    GetPlayerName(playerid,n,MAX_PLAYER_NAME);
    format(file,sizeof(file),"VIP SYSTEM/Users/%s.txt",n);
    return 1;
}

If you don't know how to work with dcmd put the dcmd_command outside any callback.