Cache problem for out of country zone

[mark]

I use NT with sp5 at my ISP.  I have a customer who cannot get to
www.magotteaux.com.br.

If I look at the cache entry, it has the correct info (IP) but only the A
record.  If I delete the cache record
and try it works.  The interesting thing is it comes back with the A record,
Cname, and NS.  After a few
times going to it it stops working again.  Its only a problem with this one
domain that I know of.  Help!