One host hanging on connect

[yary]

I have tramp working via plink, but there's one host it fails to
connect with. The messages say:

Tramp: Opening connection for address@hidden using plink...
Tramp: Waiting 60s for local shell to come up...
Tramp: Sending command `plink yary.ack.org -l yary  -ssh && exit || exit'
Tramp: Waiting for prompts from remote shell
Tramp: Found remote shell prompt on `yary.ack.org'

and at that point hangs. I turned on debug-on-quit/C-g, and the stack
trace at that point is at the end of the message. It made me wonder if
that host has a problem with uname, so I ran it:

-bash-2.05b$ echo "`uname -sr`" 2> /dev/null ; echo tramp_exit_status $?
OpenBSD 3.9
tramp_exit_status 0

Any idea how to fix this hanging? thanks in advance...

here's the backtrace:

Debugger entered--Lisp error: (quit)
  accept-process-output(#<process *tramp/plink address@hidden> 1 nil)
  byte-code(" (binary garbage) " [timeout with-timeout-tag
with-timeout-timer with-timeout-timers proc timeout-msecs
run-with-timer 1 nil with-timeout-handler accept-process-output
with-timeout-value] 6)
  tramp-accept-process-output(#<process *tramp/plink address@hidden> 1)
  tramp-wait-for-regexp(#<process *tramp/plink address@hidden> nil "
?\n///a69fd6265c573004a0ca40f01152bf33
?\n")
  tramp-wait-for-output(#<process *tramp/plink address@hidden>)
  tramp-send-command(["plink" "yary" "host.asite.org" ""] "echo
\\\"`uname -sr`\\\" 2>/dev/null; echo tramp_exit_status $? ")
  tramp-send-command-and-check(["plink" "yary" "host.asite.org" ""]
"echo \\\"`uname -sr`\\\"")
  tramp-barf-unless-okay(["plink" "yary" "host.asite.org" ""] "echo
\\\"`uname -sr`\\\"" "`%s' returns with error" "echo \\\"`uname
-sr`\\\"")
  tramp-send-command-and-read(["plink" "yary" "host.asite.org" ""]
"echo \\\"`uname -sr`\\\"")
  tramp-open-connection-setup-interactive-shell(#<process *tramp/plink
address@hidden> ["plink" "yary" "host.asite.org" ""])
  tramp-maybe-open-connection(["plink" "yary" "host.asite.org" ""])
  tramp-send-command(["plink" "yary" "host.asite.org" ""] "cd ~; pwd")
  tramp-handle-expand-file-name("/address@hidden:" nil)
  apply(tramp-handle-expand-file-name ("/address@hidden:" nil))
  tramp-sh-file-name-handler(expand-file-name "/address@hidden:" nil)
  apply(tramp-sh-file-name-handler expand-file-name
("/address@hidden:" nil))
  tramp-file-name-handler(expand-file-name "/address@hidden:" nil)
  expand-file-name("/address@hidden:")
  find-file-noselect("/address@hidden:" nil nil t)
  find-file("/address@hidden:" t)
  call-interactively(find-file)