what does it mean

gistfile1.txt

[194][default:/src:0]# hab pkg exec smith/delivery-ctl delivery-ctl help
✗✗✗
✗✗✗ Exec format error (os error 8)
✗✗✗
[195][default:/src:1]# echo $?
1
[196][default:/src:0]# env PATH=$(hab pkg path core/ruby)/bin:$PATH $(hab pkg path smith/delivery-ctl)/bin/delivery-ctl help
omnibus-ctl: command (subcommand)
General Commands:
  cleanse
    Delete *all* delivery data, and start from scratch.
...
[197][default:/src:0]# echo $?
0

with RUST_LOG=debug

[198][default:/src:0]# env RUST_LOG=debug hab pkg exec smith/delivery-ctl delivery-ctl help
DEBUG:habitat_common::ui: InputStream(stdin): { is_a_terminal(): true }
DEBUG:habitat_common::ui: OutputStream(stdout): { is_colored(): true, supports_color(): true, is_a_terminal(): true }
DEBUG:habitat_common::ui: OutputStream(stderr): { is_colored(): true, supports_color(): true, is_a_terminal(): true }
DEBUG:hab: clap cli args: ["hab", "pkg", "exec", "smith/delivery-ctl", "delivery-ctl"]
DEBUG:hab: remaining cli args: ["help"]
INFO:hab::command::pkg::exec: Setting: PATH='/hab/pkgs/smith/delivery-ctl/0.0.1/20161109205929/bin:/hab/pkgs/core/coreutils/8.25/2016103104231
5/bin:/hab/pkgs/core/ruby/2.3.1/20161102184006/bin:/hab/pkgs/core/acl/2.2.52/20161031042300/bin:/hab/pkgs/core/attr/2.4.47/20161031042251/bin:
/hab/pkgs/core/glibc/2.22/20160612063629/bin:/hab/pkgs/core/grep/2.22/20161031042639/bin:/hab/pkgs/core/libcap/2.24/20161031042313/bin:/hab/pk
gs/core/libtool/2.4.6/20161031043757/bin:/hab/pkgs/core/ncurses/6.0/20161102154037/bin:/hab/pkgs/core/openssl/1.0.2j/20161102155324/bin:/hab/p
kgs/core/pcre/8.38/20161031042618/bin:/hab/pkgs/core/sed/4.2.2/20161031042459/bin'
INFO:hab::command::pkg::exec: Running: /hab/pkgs/smith/delivery-ctl/0.0.1/20161109205929/bin/delivery-ctl help
DEBUG:habitat_core::os::process::linux: Calling execvp(): ("/hab/pkgs/smith/delivery-ctl/0.0.1/20161109205929/bin/delivery-ctl") ["help"]
✗✗✗
✗✗✗ Exec format error (os error 8)
✗✗✗