zone file problem

[Pongo]

Hi all, and sorry for the trivial question, BUT:
I am not able to make lookup work for a domain instead I use a third
level domain attached; I will explain better:

to solve example.com I can nslookup ns.example.com, mail.example.com
(also the CNAME) www.example.com but NOT the only example.com .
I followed dns howto to build my zona file as below shown:

@  1D IN SOA       ns.examole.com. root.example.com. (
                                        2005052501
                                        86400
                                        30M
                                        1W
                                        1D )
;
                        NS              ns
                        NS              ns1.example.com.
                        MX      10      mail
;
localhost               A               127.0.0.1
ns                      A               xxx.xxx.xxx.xxx
dns2.nic.it             A               xxx.xxx.xxx.yyy
mail                    A               xxx.xxx.xxx.xxx
;1                      1D IN PTR       localhost.
www                     CNAME           ns

--------------------
in named.conf:
  zone "example.com" {
          type master;
          notify yes;
          file "example.com";
  };

---------------------

Regards,
Pongo