[O] Bug: `org-capture-templates' file+headline target does not accept string variable [8.2.10 (8.2.10-elpa @ c:/Users/louis/AppData/Roaming/.emacs.d/elpa/org-20141013/)]

[Louis Chan]

Having a template inside `org-capture-templates`, which uses the
file+headline target, with a string variable as its third argument (the
node headline), makes the command `org-capture` fail (specifically, when
selecting this particular template that uses this target).
The heading I have chosen, "Tasks", does exist within the file selected
within the template. When I use a variable that contains the string
"Tasks", the command fails. However, when I use the literal string
"Tasks" instead, the command succeeds and works fine.


Emacs  : GNU Emacs 24.3.1 (i386-mingw-nt6.1.7601)
 of 2013-03-17 on MARVIN
Package: Org-mode version 8.2.10 (8.2.10-elpa @
c:/Users/louis/AppData/Roaming/.emacs.d/elpa/org-20141013/)

current state:
==============
(setq
 org-ctrl-c-ctrl-c-hook '(org-babel-hash-at-point
org-babel-execute-safely-maybe)
 org-tab-first-hook '(org-hide-block-toggle-maybe
org-src-native-tab-command-maybe
                      org-babel-hide-result-toggle-maybe
                      org-babel-header-arg-expand)
 org-cycle-hook '(org-cycle-hide-archived-subtrees org-cycle-hide-drawers
                  org-cycle-hide-inline-tasks org-cycle-show-empty-lines
                  org-optimize-window-after-visibility-change)
 org-agenda-before-write-hook '(org-agenda-add-entry-text)
 org-speed-command-hook '(org-speed-command-default-hook
                          org-babel-speed-command-hook)
 org-babel-pre-tangle-hook '(save-buffer)
 org-occur-hook '(org-first-headline-recenter)
 org-metaup-hook '(org-babel-load-in-session-maybe)
 org-confirm-elisp-link-function 'yes-or-no-p
 org-capture-templates '(("t" "Todo" entry
                          (file+headline main-org-file tasks-heading)
                          "* TODO %?\n %i\n %a")
                         )
 org-default-notes-file "~/org/main.org"
 org-clock-out-hook '(org-clock-remove-empty-clock-drawer)
 org-mode-hook '(#[nil "\300\301\302\303\304$\207"
                   [org-add-hook change-major-mode-hook
org-show-block-all append
                    local]
                   5]
                 #[nil "\300\301\302\303\304$\207"
                   [org-add-hook change-major-mode-hook
org-babel-show-result-all
                    append local]
                   5]
                 org-babel-result-hide-spec org-babel-hide-all-hashes
                 org-indent-mode)
 org-metadown-hook '(org-babel-pop-to-session-maybe)
 org-agenda-files '("~/org/main.org")
 org-src-mode-hook '(org-src-babel-configure-edit-buffer
                     org-src-mode-configure-edit-buffer)
 org-after-todo-state-change-hook '(org-clock-out-if-current)
 org-confirm-shell-link-function 'yes-or-no-p
 )