Bad free() ignored
   (S) An internal routine called free() on something
   that had never been malloc()ed in the first place.
   Mandatory, but can be disabled by setting environment
   variable PERL_BADFREE to 1.
 
   This message can be quite often seen with DB_File on
   systems with "hard" dynamic linking, like AIX and
   OS/2. It is a bug of Berkeley DB which is left
   unnoticed if DB uses forgiving system malloc().