Messege in syslog: Zone "mydomain.com" (file ns1.mydomain.com) no NS RRs found at zone top

[zz at rockstone.com]

I would appreciate anyone's input or advise.
I got error messages on my Redhat 7.0, in system message log,

Problem 1:

named error message in syslog, complaining: 
" Zone "myns.com" (file ns1.myns.zone): no NS RRs found at zone top":                         
------------------------------------------------------------------------
# /usr/sbin/ndc restart
It generates in file /var/log/messages:

Nov 19 18:43:53 NS1 named[13463]: starting.  named 8.2.2-P5 Sat Aug  5 13:21:24
EDT 2000 ^Iprospector at porky.devel.redhat.com:/usr/src/bs/BUILD/bind-8.2.2_P5/src
/bin/named
Nov 19 18:43:53 NS1 named[13463]: hint zone "" (IN) loaded (serial 0)
Nov 19 18:43:53 NS1 named[13463]: Zone "myns.com" (file ns1.myns.zone): no NS RR
s found at zone top
Nov 19 18:43:53 NS1 named[13463]: master zone "myns.com" (IN) rejected due to er
rors (serial 2000111917)
Nov 19 18:43:53 NS1 named[13463]: master zone "0.0.127.in-addr.arpa" (IN) loaded
 (serial 1997022700)
Nov 19 18:43:53 NS1 named[13463]: Zone "16.172.in-addr.arpa" (file rever.myns.zo
ne): no NS RRs found at zone top     

------------------------------------------------------------------------
Problem 2:
Underscore character "_" in host name, e.g. if host name containins
 "_", such as iss_demoserver, in A record, then named generates
such error in message log: 

iss_demos   IN      A        172.16.1.13 ; this record generates error.

Nov 19 17:22:10 NS1 named[13210]: owner name "iis_demo.myns.com" IN (primary) is
 invalid - rejecting
Nov 19 17:22:10 NS1 named[13210]: ns1.myns.zone:134: owner name error
Nov 19 17:22:10 NS1 named[13210]: ns1.myns.zone:134: Database error near (A)

But if change it so the CNAME contains "_" then the error message do not
happen again. why? 

issdemos    IN      A        172.16.1.13   ; iss_demo renamed to issdemos
iss_demos   IN      CNAME    issdemos      ; this name seems works fine.                       
Following are my configuration files: 
------------------------------------------------------------------------
Contents of /etc/named.conf
options {
        directory "/var/named";
         query-source address * port 53;     
// (This dns server is behind Cisco firewall serving internal LAN only)
//
zone "." IN {
        type hint;
        file "named.ca";
};
zone "myns.com" IN {
        type master;
        file "ns1.myns.zone";
        allow-update { none; };
};
zone "0.0.127.in-addr.arpa" IN {
        type master;
        file "named.local";
        allow-update { none; };
};
zone "16.172.in-addr.arpa" IN {
        type master;
        file "rever.myns.zone";
        allow-update { none; };
};                  
-----------------------------------------------------
Contents of file:  /var/named/ns1.myns.zone 

$TTL    864000
@       IN      SOA     ns1.myns.com. mymail-hq (
                        2000111917      ; serial number
                        28800           ; Refresh
                        14400           ; Retry
                        720000          ; expire
                        604800)         ; deafult TTL
172.16.1.200    IN      NS              ns1.myns.com.
172.16.1.201    IN      NS              ns2.myns.com.
                IN      MX      10      mymail-hq.myns.com.
                IN      MX      30      my2ndmail.myns.com.        
dragon               IN  A     172.16.1.3       ; Internal LAN Server1 
phoenix              IN  A     172.16.1.6
mybdc-02             IN  A     172.16.1.12      ; My 2nd BDC
mybdc03              IN  A     172.16.1.13      ; My 3rd BDC  
.....
-----------------------------------------------------------------------
Contents of reverse zone file:  /var/named/rever.myns.zone
$TTL    864000
@                       IN      SOA     ns1.myns.com. mymail-hq (
                        2000111917      ; serial number
                        28800           ; refresh
                        14400           ; retry
                        720000          ; expire
                        604800)         ; deafult TTL
200.1      IN  NS    ns1.myns.com.
201.1      IN  NS    ns2.myns.com.    
3.1        IN  PTR   dragon.myns.com.
6.1        IN  PTR   phoenix.myns.com.
12.1       IN  PTR   sstbdc-02.ssti.com.
13.1       IN  PTR   sstbdc03.ssti.com.   
......
-----------------------------------------------------------------------

Could any one see anything wrong with my configration? 
thanks.