[erlang-questions] Tuple problem

[Pat e]

How do i get same effect on parse_post tuple result like i get with for example:
P = {"key","value"},
S = element(2,P),

and it of course gives "value" result, but when i post data to R =
yaws_api:parse_post(Arg) i also get result {"key","value}, only when i
try S = element(2, R) the return is error:

Reason: {badarg,[{m3,out,1},
                {yaws_server,deliver_dyn_part,8},
                {yaws_server,aloop,3},
                {yaws_server,acceptor0,2},
                {proc_lib,init_p,5}]}

I hoped that i would grasp Erlang and Yaws in 2 to 3 weeks but it
seems it will take 2 to 3 months just for basics :(

Also when i extract element from tuple how do i return it without
quotes, i.e. "value" to become just value?

Thanks :)