switching from/to X -query display

[Gerhard Kroder <Gerhard.Kroder@data-sciences.de>]

i have an sun-server accessable to run remote  X sessions (dtlogin
fetched with X -query ...). logging onto the sun works fine, switching
back to local (linux) X with ctrl-alt-f7 is fine, too. but switching to
sun's display back again i run in trouble. all i can see is a black
screen with a tty-style output  like "Erase is  delte \n Kill is
control-U" and such.  i see no way to recover to real display.  i had
this remote display running some weeks ago without this problem.
meantime i updatet my woody sytem.

any hints?
  gerhard