could not find the specified host for communications (http,ping,etc) but can resolve with nslookup

Communication to internal sites fail.

Network Background: Netware 6.5 sp6 Servers, Windows XP SP2 clients.
DNS is running on the novell server resolving internal dns and external dns.

Problem:  External dns works fine.  Internal DNS is flaky.  This problem is intermittent but seems to be manifesting itself more and more.  we will use my helpdesk software server as the example.  It's DNS is helpdesk.gsd.  

On some clients, when you try to go to http://helpdesk.gsd, you get a page cannot be displayed error.  Diving deeper in to the problem, I have discovered that you can not ping the server via DNS name, but you can ping via IP.  when pinging via dnsname you get "could not find the specified host".  The strange part is that NSLookup performs flawlessly.  You do "nslookup helpdesk.gsd" and the IP is displayed successfully.  After doign this, the URL still does not work.  Manually flushing the dns (ipconfig /flushdns) does not help.  The only way I have found to fix it, is to release and renew the machiens dhcp info, and then everything seems to work fine.  

This is also happening on multiple models of machines, so I do not believe it is a bad image or anything unique to that specific machine.

I do not believe it is the server itself, as we have 8 servers running dns, and this is happening at all buildings.  Also I have restarted Named (dns server application) multiple times to no avail.

Any Ideas?