[Konstantinos]

@Above users, it's params, not cmdtext. Also, it's not necessary to use sscanf for it. That's why there's 'isnull'.
Last, never use a cell of 256 in client/player message. The limit is only 128.

pawn Код:

#define isnull(%1) \
    ((!(%1[0])) || (((%1[0]) == '\1') && (!(%1[1]))))

pawn Код:

CMD:v( playerid, params[ ] )
{
    if( playerDB[ playerid ][ vip ] )
    {
        if( isnull( params ) ) return SendClientMessage( playerid, GREEN, "* Naudojimas: /v [tekstas]" );
        new
            zin[ 128 ]
        ;
        format( zin, sizeof( zin ), "VIP: %s", params );
        SendClientMessageToAll( GREEN, zin );
    }
    return 1;
}