1) jam echo area with manually deleted messages scans only with -w parameter
   (whithout highwaters)
2) when hpt coudn't write msg (or open area) hpt renames .pkt to .err
   but message, which wasn't written to msgbase will be in dupeArea,
   because hpt saved its dupeEntry to dupeBase in first tossing...
3) under win32 & watcom c (others compilers didn't tested for this problem)
   system() returns 0 if unpacker does not found, so arcmail will be lost...
