module not loading msgpack erlang - module

Question

Attempting to test msgpack as dependency in a simple release package using rebar in Erlang / OTP.
My folder structure is as follows
Project -> Apps -> myapp -> ebin
-> src
-> deps -> msgpack (folder)
-> rebar (exe)
-> rebar config
-> rel -> reltool.config
-> files (folder)
-> mynode (folder)
Code snippet of the function & its handle_call:
num_pokes() ->
gen_server:call(?MODULE, num_pokes).
handle_call(num_pokes, _From, State = #state{ num_pokes = PokeCount }) ->
MP = msgpack:pack(PokeCount),
io:format (" Message is packed : ~p~n", MP),
MuP = msgpack:unpack_stream(MP),
io:format (" Message is now UNpacked : ~p~n", MuP),
io:format (" Pokecount : ~p~n", PokeCount),
{reply, PokeCount, State};
Error showing: when num_pokes() is called
=ERROR REPORT==== 10-Apr-2015::12:44:53 ===
** Generic server myapp_server terminating
** Last message in was num_pokes
** When Server state == {state,2}
** Reason for termination ==
** {'module could not be loaded',
[{msgpack,pack,[2],[]},
{myapp_server,handle_call,3,[{file,"src/myapp_server.erl"},{line,32}]},
{gen_server,try_handle_call,4,[{file,"gen_server.erl"},{line,607}]},
{gen_server,handle_msg,5,[{file,"gen_server.erl"},{line,639}]},
{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,237}]}]}
** exception exit: {{undef,
[{msgpack,pack,[2],[]},
{myapp_server,handle_call,3,
[{file,"src/myapp_server.erl"},{line,32}]},
{gen_server,try_handle_call,4,
[{file,"gen_server.erl"},{line,607}]},
{gen_server,handle_msg,5,
[{file,"gen_server.erl"},{line,639}]},
{proc_lib,init_p_do_apply,3,
[{file,"proc_lib.erl"},{line,237}]}]},
{gen_server,call,[myapp_server,num_pokes]}}
in function gen_server:call/2 (gen_server.erl, line 182)

Answer 1

Pass -pa deps/msgpack/ebin to erl as command-line arguments. Then it will find the compiled modules.

Answer 2

Folder structure pointing towards mspack was shown by me as ./deps (dependencies folder). It should be ./deps/msgpack