[Correlli]

It's better if you use 'playerid' instead of 'i' here:

pawn Код:

Name(playerid)
{
new n[24];
GetPlayerName(playerid, n, 24);
return n;
}

This is correct:

pawn Код:

if(!strcmp(cmdtext, "/b", true))
{
for(new i = 0; i < MAX_PLAYERS; i++)
{
if(GetDistanceBetweenPlayers(playerid, i) <= 20)
{
if(cmdtext[2] == 32 || cmdtext[3] != EOS)
{
new str[128];
format(str, 128, "%s: %s", Name(playerid), cmdtext[3]);
SendClientMessage(i, COLOR_WHITE, str);
}
}
}
return true;
}

And you also need 'GetDistanceBetweenPlayers' function. Search in scripting-boards for it.