client host or user not trusted by the server - nos uch file or directory

hello all! the strange part of this message is that it supplies a user - informix@oma-isa-kabul.com - which is a windows machine that no longer exists on our network (we have a windows 2000 domain with Active Directory). The network people have looked in DNS and various places but do not see the entry for this old machine. This error occurs when trying to run a select sql across servers and databases but not when run across just databases. We are using version 9.21-HC5-1 on a HP-UNIX 11.00... Has anyone run across this before? Thanks for any info. Tom