Remote Client Access Printer session security error -- MIDRANGE-L

One of our remote clients has a peculiar problem with Client Access printer
session that I can't figure out.

 They recently moved their AS/400's, a 170 at v4r4, and a 40s at v4r2, to a
new office, and now many of their remote users have lost the ability to
connect a Client Access printer session to the 170.

They now get an error "CWBUNPLA:  Error occurred while retrieving usage
information or user XXXXXX on system YYYYYY" when they try to connect to the
170, but not when they connect to the 40s. The same message appears when
trying to connect with OpsNav, followed by "AS/400 Operations Navigator: A
security error has occurred". I verified these messages from my location,
although I can still connect to all of our other clients' /400's with OpsNav
and Client Access sessions.

They are connected to the internet with a business DSL line, same as in
their old location, although from a different provider. They use a pair of
Linksys Cable Modem/DSL routers on 2 of their external IP's off the DSL
modem, and all the necessary Client Access ports are NAT'ed on the Linksys
to point to their respective /400's. I've had their in-house tech guy check
the correct ports are being used, everything is plugged in right, and
allegedly nothing has changed other than the physical location.

My suspicion is that the DSL line is the culprit. Nothing else has changed,
and local user have no problem connecting their printer sessions. We've even
tried to create new sessions from scratch on a new PC at a remote site.
Nobody will admit to changing anything on the /400 itself, and I've check
the TCP/IP routes and DNS settings, and everything looks right. Of course,
the tech's at the DSL company have no idea what an AS/400 is, and can't
understand why I need all these wacky IP ports, but they everything is OK on
their side, it must be a configuration problem on our 'mainframe'.

What's driving me nuts is that not ALL the remote printers sessions are on
the fritz. A little less than half of them work just fine, after they
changed the IP address of the /400 in the PC's HOSTS file. The PC's that
work and the ones that don't 'appear' to have identical config's, at least
it looks that way from walking the people at the remote sites through the
Client Access config. I can connect a telnet display session, both with
Client Access and Mochasoft( I get the "error retrieving usage information"
with C/A, but it connects).

Any ideas of suggestions are appreciated(including RTFM references). I've
checked the midrange-l archives, and browsed through Infoseek, but haven't
been able to come up with anything.

-------------
Lou Schmaus
CCA, Inc.
lschmaus@link400.com