NW 6.5 SP3 to OES Linux SP1
XP-Pro SP2, NW Client 4.91 SP1

After "Initializing SMS connections between servers"

Error '(You may be able to look in SYS\SYSTEM\MIGERROR.LOG file on the
destination and/or source server for more information about this error.)
SMSConnOpen Xfffdffdd - NWSMTS error: One or more of the parameters are
null or invalid.' occurred attempting to open the connection to the SMDR
from server 'FS1' to server 'FS2'. Make sure the TSA and SMDR nlms are
loaded on the source and that the SMS modules are running on the Linux
server. If SLP is not configured, you may need to edit the source
server's SYS:ETC/HOSTS file, and insert an entry for the destination
Linux server (include IP address and server name). See the
Troubleshooting section in the user documentation for possible solutions
to this connection error.

Yep, they are loaded. Yep, everything is in the HOSTS file on both
servers. What else?