Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  looking-at(nil)
  (save-excursion (beginning-of-line 1) (looking-at org-todo-line-regexp))
  (and (outline-on-heading-p) (not (bolp)) (save-excursion (beginning-of-line 1) (looking-at org-todo-line-regexp)) (< (point) (+ 2 ...)))
  (if (and (outline-on-heading-p) (not ...) (save-excursion ... ...) (< ... ...)) (progn (goto-char ...) (and ... ...)))
  (let* ((match-data ...) (startpos ...) (logging ...) (org-log-done org-log-done) (org-log-repeat org-log-repeat) (org-todo-log-states org-todo-log-states) (this ...) (hl-pos ...) (head ...) (ass ...) (interpret ...) (done-word ...) (final-done-word ...) (last-state ...) (completion-ignore-case t) (member ...) (tail ...) (state ...) (state ...) (next ...) (change-plist ...) dolog now-done-p) (when org-blocker-hook (setq org-last-todo-state-is-todo ...) (unless ... ...)) (store-match-data match-data) (replace-match next t t) (unless (pos-visible-in-window-p hl-pos) (message "TODO state changed to %s" ...)) (unless head (setq head ... ass ... interpret ... done-word ... final-done-word ...)) (when (memq arg ...) (message "Keyword-Set %d/%d: %s" ... ... ...)) (setq org-last-todo-state-is-todo (not ...)) (setq now-done-p (and ... ...)) (and logging (org-local-logging logging)) (when (and ... ... ...) (setq dolog ...) (if ... ...) (when ... ...) (when ... ... ...) (when ... ...)) (org-todo-trigger-tag-changes state) (and org-auto-align-tags (not org-setting-tags) (org-set-tags nil t)) (when org-provide-todo-statistics (org-update-parent-todo-statistics)) (run-hooks (quote org-after-todo-state-change-hook)) (if (and arg ...) (setq head ...)) (put-text-property (point-at-bol) (point-at-eol) (quote org-todo-head) head) (when now-done-p (when ... ...) (org-auto-repeat-maybe state)) (if (and ... ... ... ...) (progn ... ...)) (when org-trigger-hook (save-excursion ...)))
  (catch (quote exit) (org-back-to-heading t) (if (looking-at org-outline-regexp) (goto-char ...)) (or (looking-at ...) (looking-at " *")) (let* (... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... dolog now-done-p) (when org-blocker-hook ... ...) (store-match-data match-data) (replace-match next t t) (unless ... ...) (unless head ...) (when ... ...) (setq org-last-todo-state-is-todo ...) (setq now-done-p ...) (and logging ...) (when ... ... ... ... ... ...) (org-todo-trigger-tag-changes state) (and org-auto-align-tags ... ...) (when org-provide-todo-statistics ...) (run-hooks ...) (if ... ...) (put-text-property ... ... ... head) (when now-done-p ... ...) (if ... ...) (when org-trigger-hook ...)))
  (save-excursion (catch (quote exit) (org-back-to-heading t) (if ... ...) (or ... ...) (let* ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...)))
  (let ((org-blocker-hook org-blocker-hook) (case-fold-search nil)) (when (equal arg ...) (setq arg nil org-blocker-hook nil)) (when (and org-blocker-hook ...) (setq org-blocker-hook nil)) (save-excursion (catch ... ... ... ... ...)))
  org-todo(right)
  call-interactively(org-todo)
  (let ((current-prefix-arg arg)) (call-interactively command))
  org-call-with-arg(org-todo right)
  (let ((org-inhibit-logging ...) (org-inhibit-blocking ...)) (org-call-with-arg (quote org-todo) (quote right)))
  (cond ((run-hook-with-args-until-success ...)) ((and org-support-shift-select ...) (org-call-for-shift-select ...)) ((org-at-timestamp-p t) (call-interactively ...)) ((and ... ...) (let ... ...)) ((or ... ...) (org-call-with-arg ... nil)) ((and ... ...) (call-interactively ...)) ((org-clocktable-try-shift ... arg)) ((run-hook-with-args-until-success ...)) (org-support-shift-select (org-call-for-shift-select ...)) (t (org-shiftselect-error)))
  org-shiftright(nil)
  call-interactively(org-shiftright nil nil)