Thanks for that. The reason I am confused is that my actual servername (which is correctly returned by using SERVERPROPERTY('servername')), differs from the DNS name used for the server.

In my...

Yeah, I did include the @local parameter. this has added the servername to syservers but has not resloved the DTS auth problem unfortunately. beginning to suspect it may be a...

Well using sp_addserver has added the server to the syservers table but @@servername still brings a result of NULL. Does the service require restart to update @@servername?

Well that did occure to me, but all the DTS packages that are failing were local to the problematic server, not connecting to any other. Why should the server require...