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 )