Update: I guess I goofed on the problem. Ooops. Sorry. Since, you don't have an each() loop in the Perl source code, I guess there must be something that is not in your Perl source code causing the error, which would I guess mean something in XS code? I am unable to imagine how this can happen otherwise.

I took the pragmatic approach and re-coded the loop to use a foreach() loop over (keys %$happy_camper) instead of trying to get the combined key,val each() iterator to work. I haven't had trouble adding keys with a foreach loop like below. Tested on Perl 5.20 MSWin32.

#!/usr/bin/env perl

use strict;
use warnings;
use Data::Dump qw(pp);

EXAMPLE:
{
  my $happy_camper =
    {
      Rambler   => 'The Yellow Rose of Texas',
      Wagon     => 'There may be flies on them there guys but there ar
+e no flies on us',
      Caskit    => 'The Rain in Spain goes mainly down the drain',
      Skate     => 'The Quick Brown Fox Jumped Over The Lazy Dogs Back
+',
      Lemon     => 'Love the smell of napalm in the morning'
    };

  my $newkeys = 'KEYME000';

  foreach ( 1 .. 900000 )
  {
    foreach  my $_key (keys %$happy_camper)
    {
      if ( int(rand 300000) == 1 )
      {

        $happy_camper->{ ++$newkeys } = 'Shame on you!';

      }
    }
  }
  pp $happy_camper;
}


exit 0;
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