diff --git a/nsis/getpearch.pl b/nsis/getpearch.pl
index 25155536..77fdb575 100644
--- a/nsis/getpearch.pl
+++ b/nsis/getpearch.pl
@@ -5,6 +5,7 @@
 #
 
 use strict;
+use bytes;
 
 my %archnames = (
     0x01de => 'am33',
@@ -38,8 +39,8 @@ read($fh, my $mz, 2);
 exit 0 if ($mz ne 'MZ');
 
 exit 0 unless (seek($fh, 0x3c, 0));
-exit 0 unless (read($fh, my $pe_offset, 1) == 1);
-$pe_offset = unpack("C", $pe_offset);
+exit 0 unless (read($fh, my $pe_offset, 4) == 4);
+$pe_offset = unpack("V", $pe_offset);
 
 exit 0 unless (seek($fh, $pe_offset, 0));
 read($fh, my $pe, 4);