The enc. message lacks the needed newlines. There must be a line break after the ---BEGIN ... --- line and two after the version line. Then one every 65 characters until the --- END .. --- line which has to start with one.

Change the my $PGPEncryptedMessage line to: 

my $PGPEncryptedMessage = <<'EOM';
-----BEGIN PGP MESSAGE-----
Version: haneWIN JavascriptPG v2.0

hIwDAAAAAAAAAAABA/4oJfsBR88yts6eY22RJDwEFyhxi2KWIJx6BR8fufIDN4j3
H79sCTN3UHDYoCV5zluSyhdSmM8beF1+hQ7PvSsonDOXrGfovIb9/cItQQg1CrgI
63Xje85qWW3IUpebnt4UlPnXx1sxK46GtJIEckYppWbXubCunAdFhhCyiq4ZBqQn
Z9EAojfFrI8zkVIC/gq7cMZsu1wgn7/lcUvFewUNWWrU8ykAiC5t=R2eG
-----END PGP MESSAGE-----
EOM

[download]
It's also better to use single quotes for such texts to avoid accidental expansion. Ok, ` $ @ & might not be valid anyway in PGP messages.

PS: my $arg; should be my %arg;. Just add 

use strict;
use warnings;

[download]
at the very start of you script.

In reply to Re: Decrypting a message with Crypt::OpenPGP by mscharrer
in thread Decrypting a message with Crypt::OpenPGP by willjones

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