On a server running irix-6.5 and amanda 2.5.1p2
planner debug shows:

security_getdriver(name=bsdtcp) returns 4075aa8
security_handleinit(handle=1001d4a8, driver=4075aa8 (BSDTCP))
security_streaminit(stream=1005e538, driver=4075aa8 (BSDTCP))
security_close(handle=1001cfe0, driver=4075aa8 (BSDTCP))
security_stream_close(10053a80)
security_stream_seterr(1005e538, SOCKET_EOF)
security_seterror(handle=1001d4a8, driver=4075aa8 (BSDTCP) error=EOF
on read from yorick)
security_close(handle=1001d4a8, driver=4075aa8 (BSDTCP))
security_stream_close(1005e538)

and the amanda report shows things like:

  yorick  DATA_sub101   lev 0  FAILED [hmm, disk was stranded on waitq]
  planner: ERROR Request to yorick failed: EOF on read from yorick

and the backup fails. The funny thing is that I have 2 other configurations
running 2.5.1p2 in parallel that doesn't exhibit this behaviour.
Any clues?
jf