Local DNS queries fall without FQDN

My DNS server is an NT 4.0 box, when I try to do a NSLOOKUP on some WIN2K servers it fails. It works on NT boxs and 1 WIN 2K box. Below is example!
nslookup myserver
DNS response ” name does not exist”
nslookup myserver.com
DNS response “myserver.com 10.1.1.1”
When I look at a packet capture on the DNS server I see the NT boxs and 1 WIN2K box send my server.com., but the other 2k servers send myserver.it look as if some of the servers are appending the FQDN to the query.