The following script works without errors, but /tmp/test.touch is not being created (even being checked later in the command line). It seems to me as if $r->spawn_proc_prog doesn't spawn a process. What may cause the problem?

#!/usr/bin/perl
use strict;
use warnings;

use Apache2::RequestUtil;
use Apache2::SubProcess ();

my $r = Apache2::RequestUtil->request;

print "Content-Type: text/plain\n\n";

print eval { $r->spawn_proc_prog('/usr/bin/touch', ['/tmp/test.touch']) }
    ? `ls -l /tmp/test.touch`
    : $@;