Hm-m, suppose:

use strict;
use warnings;
use IPC::Run qw( start );

my @c = qw( cmd /c sort );
my $h = start \@c, '<pipe', \*IN, '>pipe', \*OUT;
print IN "zzz...\n";
print IN "hello world\n";
close IN;
pump $h;
print uc while <OUT>;
close OUT;
finish $h;
[download]

to print uppercased sorted lines:

HELLO WORLD
ZZZ...
[download]

But if packed to executable:

pp -o pack_test.exe pack_test.pl
[download]

the pack_test.exe gives:

Inappropriate I/O control operation: Win32::Process::Create() at C:\Us
+ers\me\AppData\Local\Temp\par-766164696d\cache-2f8c1556e4a094e1c7eee6
+ea88e299192e77e2e4\inc\lib/IPC/Run.pm line 2150.
Inappropriate I/O control operation: Win32::Process::Create() at C:\Us
+ers\me\AppData\Local\Temp\par-766164696d\cache-2f8c1556e4a094e1c7eee6
+ea88e299192e77e2e4\inc\lib/IPC/Run.pm line 2251.
[download]

Looks like Win32::Process::Create wants absolute path at #345, and IPC::Run::Win32IO is overly optimistic to find it in $^X. Within PAR, this variable contains just 'perl.exe'. Even if there's no such file on the system.

In fact, I don't know how to properly invoke perl from PAR bundle (it does contain all binaries, doesn't it), so here's a dirty hack. Somewhere at line #311, put

local $^X = $ENV{ PAR_TEMP } . '\inc\perl.exe'
    if $^X eq 'perl.exe' and exists $ENV{ PAR_TEMP };
[download]

And then pack like this:

pp -M IPC::Run::Win32Pump -a C:\berrybrew\strawberry-perl-5.32.1.1-64b
+it-PDL\perl\bin\perl.exe;perl.exe -o pack_test.exe pack_test.pl
[download]

and then pack_test.exe kindly gives:

HELLO WORLD
ZZZ...
[download]

I have no idea if it's IPC::Run or PAR::Packer (or Perl itself built on Windows) fault; and whether it'll work for your multi-gigabyte multi-threaded app; and how many refined professionals dropped unconscious because of ugliness of the above hack, but it's something to start with.