When clocking in under a headline that already has clock entries, the
entries are not correclty bundled in a drawer, generating a: (I removed
the bytecode because gmail didn't like it)

Debugger entered--Lisp error: (wrong-type-argument char-or-string-p nil)
  byte-code("REMOVED" [beg end org-clock-into-drawer drawer find-unclosed
org-clock-string line-beginning-position outline-next-heading
org-clock-drawer-name "^[ ]*" "
\\[\\([0-9]\\{4\\}-[0-9]\\{2\\}-[0-9]\\{2\\}" " *\\sw+
+[012][0-9]:[0-5][0-9]\\)\\][ ]*$" re-search-forward t org-element-at-point
org-element-type clock org-element-property :status running
beginning-of-line throw exit "^[ ]*:" regexp-quote ":[ ]*$" :contents-end
nil 0 org-end-of-meta-data "\n" wholenump 2 ":" ":\n:END:\n"
org-indent-region org-flag-drawer mapconcat #[(p) "\212
b\210\302\212\303\304x\210\305\306!)\305\306!\"
\307\310\311\307\312\311 ##*\207"
[p s delete-and-extract-region "
\n" nil line-beginning-position 2 replace-regexp-in-string "\\`[ \n
]+" "" "[ \n
]+\\'"] 7] "\n:END:\n" point-marker ":\n" -1 last open-clock-re element
drawer-re cend org-log-states-order-reversed first ...] 4)
  org-clock-find-position(nil)
  byte-code("REMOVED" [org-clock-resolving-clocks-due-to-idleness
org-clock-resolving-clocks org-clock-leftover-time leftover org--msg-extra
target-pos org-clocking-p nil "" t org-resolve-clocks (64) org-clock-in (4)
org-clock-select-task "Clock-in on task: " copy-marker error "Abort" (16)
org-clock-mark-default-task org-back-to-heading marker-buffer
marker-position 4 org-heading-components message "Clock continues in
\"%s\"" throw abort org-clock-out org-at-heading-p point-at-bol 0
org-base-buffer run-hooks org-clock-in-prepare-hook org-clock-history-push
functionp looking-at match-string 2 org-todo "[ ]*" "\\>"
replace-regexp-in-string "\\[\\[.*?\\]\\[\\(.*?\\)\\]\\]" "\\1"
match-string-no-properties "???" ...] 8)
  org-clock-in(nil)
  call-interactively(org-clock-in nil nil)
  command-execute(org-clock-in)

that prevents the clock in
I go from

** TODO a task
CLOCK: [2016-04-29 Fri 13:14]--[2016-04-29 Fri 14:43] =>  1:29
CLOCK: [2016-05-04 Wed 12:44]--[2016-05-04 Wed 12:44] =>  0:00

C-c C-x C-i

to

** TODO a task
:CLOCK: [2016-05-04 Wed 12:44]--[2016-05-04 Wed 12:44] =>  0:00
CLOCK: [2016-04-29 Fri 13:14]--[2016-04-29 Fri 14:43] =>  1:29
:END:


Any ideas?


Carlos.


Emacs  : GNU Emacs 24.5.1 (i686-pc-cygwin)
 of 2015-06-23 on desktop-new
Package: Org-mode version 8.3.4 (8.3.4-47-gaf853d-elpa @
/home/carlos/.emacs.d/elpa/org-20160502/)

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-babel-hide-result-toggle-maybe
                      org-babel-header-arg-expand)
 org-archive-hook '(org-attach-archive-delete-maybe)
 org-cycle-hook '(org-cycle-hide-archived-subtrees org-cycle-hide-drawers
                  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-blocker-hook '(org-block-todo-from-children-or-siblings-or-parent)
 org-return-follows-link t
 org-babel-pre-tangle-hook '(save-buffer)
 org-occur-hook '(org-first-headline-recenter)
 org-link-file-path-type 'relative
 org-metaup-hook '(org-babel-load-in-session-maybe)
 org-confirm-elisp-link-function 'yes-or-no-p
 org-clock-out-hook '(org-clock-remove-empty-clock-drawer)
 org-enforce-todo-dependencies t
 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-clock-into-drawer 3
 org-metadown-hook '(org-babel-pop-to-session-maybe)
 org-agenda-files '("~/notes/onto-alliance.org" "~/notes/ODASE-src.org"
                    "~/notes/notes.org")
 org-file-apps '((auto-mode . emacs) ("\\.mm\\'" . default)
                 ("\\.x?html?\\'" . default) ("\\.pdf\\'" . default)
                 (system . "open %s"))
 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-after-todo-statistics-hook '(org-summary-todo)
 org-confirm-shell-link-function 'yes-or-no-p
 )