Can you post some of the surrounding code.
I can't reproduce the error except for doing this, and doubt this is what you are doing

my %hash;
$hash{test} = {};
push @{$hash{test}}, 1, 2;

use Data::Dumper;
print Dumper \%hash;
[download]

I've tried various things like

my %hash;

#Tried these things
#$hash{test} = 'test';
#$hash{test} = 1;

push @{$hash{test}}, 1, 2;

use Data::Dumper;
print Dumper \%hash;
[download]

They all didn't have the desired result(some didn't push), but they didn't throw that error. This is on Win32 Perl 5.6.

- Tom