This is very common with Windows 2000 servers as in most cases domain name is not part of the computer name.
a. On the primary server do the following at a command prompt:
  
  cd ace/data
  sdrepmgmt list

   This will give the list of all hostnames in replica table. Note the replica name whether it is FQDN or short name.

Notice the name of the replica server. If the replica server name is not correct, delete the the replica server from the replica table and add it with the correct name.

sdrepmgmt delete

Enter the name of the replica server name.

sdrepmgmt add

Enter the correct name of the replica server name.

If you think the replica table is more accurate and there is error on replica server name on actual machine, proceed as below described:
b. On the replica server:

   My computer -->Right Click -->Properties --> Network Identification ----->Full Computer name
   Verify the hostname and if the name is matching with the hostname in the replica table.
   If the hostname does not match, Click on Properties and change the hostname.
   Hostname must be all in lower case in order to maintain consistency. Reboot the server.

c. Confirm the hostname change by running: ipconfig /all
d. Start the primary server.
e. On the primary server launch the activity monitor.
f.  Start the replica.