Help!!! MX is driving me nuts

[Ken Holmes]

Can anyone help me I have a primary domain who's dns is handled by
another server not controlled by me.  So I they set it up as
mail.primarydomain.com works great
So I set up my system as a small time DNS system so I don't have to wait
and rely on them and pay them to map multiple domains.  OK so here is my
multiple problems.
Problem #1 I used Linuxconf and netconf  <---Very Dumb move I know
OK So here is the real problem #1 I can't make my servers have a mail
server like mail.domain2.com or mail.domain3.com.  I can only get them
to work as domain2.com and domain3.com
OK now the big problem.
#2 I got 2 other domains working fine and I can send mail and receive
mail.
Now a buddy asked me for a favor and I gave him web space and I
registered his domain with Internic and I went to the server and
recreated in the same steps what I did for the other 2 domains and it
doesn't work. I got the address working like www.friendsdomain.com but I
can't get the mail server working when I try to send an email to
buddy at friendsdomain.com it bounces back and says
Host unknown (Name server: mail.friendsdomain.com.: host not found)
This is driving me crazy

I have the DNS and Bind book and went through it and set up my DB files
just like it says and I checked my named.conf file and I can't find the
problem anywheres.
I even copied my other domain that works db file and renamed it to the
one that doesn't work and changed the values to the new domain and it
still doesn't work anyone have any ideas please email me
ken at virtualworldinc.com
I can send you the related files if you are seriously interested in
helping.

Thanks in advance

Ken Holmes