Problem with E-mail (Name server timeout)

[Ted Ritchie]

We are having a problem sending e-mail to a domain (pacgtc.com). All other
e-mail delivery is working fine, but every time we try to send to this
domain we get a Name server timeout. I have deduced that if we send a
message to user at pacgtc.com. <-- note the trailing period the message will go
through. I am not very familar with DNS, but I have tried nslookup after
looking through this newsgroup. If I do an nslookup pacgtc.com I get no
responce, but if I do an nslookup after setting the type to MX I do get a
responce. This doesn't seem correct to me but I don't know what it all
means.

I would greatly appreciate it if somone could point me in the direction of
the next step(s). I don't mind if they just tell me what is wrong, but I
would prefer if I could find out how to check for myself.

Thanks,
Ted