Error in write to named pipe

I have an application that reads a file and writes  some lines to a
named pipe.  It's just a sigmonster.  On a current kernel/world from
11/11 the signature gets created and written to the pipe quite
nicely.  On a kernel/world from this morning (1600 GMT) the app fails
to write the signature.

The pipe and write portion of the ktrace is as follows:
929 signature CALL  fork
   929 signature RET   fork 930/0x3a2
   929 signature CALL  exit(0)
   931 signature RET   open 3
   931 signature CALL  pipe
   931 signature RET   pipe 4
   931 signature CALL  fork
   931 signature RET   fork 959/0x3bf
   931 signature CALL  wait4(0x3bf,0,0,0)
   931 signature RET   wait4 959/0x3bf
   931 signature CALL  close(0x5)
   931 signature RET   close 0
   931 signature CALL  read(0x4,0xbfbfdbd4,0x200)
   931 signature GIO   fd 4 read 64 bytes
       "Don't abandon hope: your Tom Mix decoder ring arrives tomorrow.
       "
   931 signature RET   read 64/0x40
   931 signature CALL  close(0x4)
   931 signature RET   close 0
   931 signature CALL  __sysctl(0xbfbfd1f0,0x2,0xbfbfd630,0xbfbfd1ec,0,0)
   931 signature RET   __sysctl 0
   931 signature CALL  __sysctl(0xbfbfd1f0,0x2,0xbfbfd730,0xbfbfd1ec,0,0)
   931 signature RET   __sysctl 0
   931 signature CALL  __sysctl(0xbfbfd1f0,0x2,0xbfbfd830,0xbfbfd1ec,0,0)
   931 signature RET   __sysctl 0
   931 signature CALL  __sysctl(0xbfbfd1f0,0x2,0xbfbfd930,0xbfbfd1ec,0,0)
   931 signature RET   __sysctl 0
   931 signature CALL  __sysctl(0xbfbfd1f0,0x2,0xbfbfda30,0xbfbfd1ec,0,0)
   931 signature RET   __sysctl 0
   931 signature CALL  write(0x3,0xbfbfe3d4,0xad)
   931 signature RET   write -1 errno 45 Operation not supported
   931 signature CALL  close(0x3)
   931 signature RET   close 0
   931 signature CALL  nanosleep(0xbfbfdb38,0xbfbfdb30)
   931 signature RET   nanosleep 0
   931 signature CALL  access(0x804b220,0)
   931 signature NAMI  "/home/dlt/.signature"
   931 signature RET   access 0
   931 signature CALL  open(0x804b220,0x1,0x400)
   931 signature NAMI  "/home/dlt/.signature"

Why would write suddenly be returning "operation not supported" when
it's to a pipe?

-- 
Derek Tattersall		dlt_at_mebtel.net    dlt666_at_yahoo.com