on *:join:#Daniel: {
if ($ulevel == 300) { mode # +b $nick | .kick # $Nick (canal Prohibido)}
elseif ($ulevel == 99) { echo -a aufvidersen | .echo -a bienvenido }}
}
}

any one tell me how is wrong?

Try this:

on *:join:#Daniel: {
if ($ulevel == 300) { mode # +b $nick | .kick # $Nick (canal Prohibido) }
elseif ($ulevel == 99) { echo -a aufvidersen | .echo -a bienvenido }
}

Notice all the extra }'s have been removed and spaces have been applied where needed

You need to make sure that those ppl are in your userlist. E.g.:

300:*!*@John.com
99:*!*itsme@Mary.com
100:*!*hi@Paula.com

and so on. That scriopt will only match the ppl that are in the Userlist, so, if John is connecting from Matt's place (*!*@Matt.com) it will not work.
Another way is to block nicks, but that isnt very accurate, since the person can just change nicks.

To add a user: /auser <level> <mask> [info]

Edit: Also landonsandor has a point You're missing some spaces.

Hope this can help!
Zyzzy