Zone File Config Problems

[Salvador Peralta]

I'm changing from a hosting company that I've used for the past several
years.  They used to handle the DNS on my co-located machine.  Now I'm
trying to set it up to handle it myself, and I'm having a few problems:

First, I'd like for NS1 and NS2 to handle DNS requests.  For some reason,
when I dig with the following configuration, I get a "Couldn't find server
'ns1.progressivetrail.org': Name or service not known" error.  This will
resolve properly if I dig @jefferson.progressivetrail.org, but not
@ns1.progressivetrail.org.

Second, the following configuration will resolve
scoobydoo.progressivetrail.org, but not the TLD progressivetrail.org.

Third, what is the purpose of the Serial line?

What changes should I make to this configuration to get things working
properly to set this up as a master for this zone?

$TTL 3D
@       IN      SOA     ns1.progressivetrail.org.
ns2.progressivetrail.org. (
                        200211152          ; serial#
                        3600            ; refresh, seconds
                        3600            ; retry, seconds
                        3600            ; expire, seconds
                        3600 )          ; minimum, seconds

                NS      ns1             ; Inet Address of nameserver
progressivetrail.org.    MX      10 mail         ; Primary Mail Exchanger
;
localhost       A       127.0.0.1
jefferson       A       67.19.14.187
ns2             A       67.19.14.188
mail            CNAME   jefferson
ns1             CNAME   jefferson
www             CNAME   jefferson
*               CNAME   jefferson

Thx,  Salvador