Hello: I tried to export an icalendar file with the current git version of org-mode and it failed. I debugged it by loading org-install on a clean Emacs with no init files and this is what I got:
,---- | Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil) | byte-code("\306 \210\203 \307 \310\216 *\204 \311 \210\312u\210\313\314\315\"\210\316\224\317\316!\320 \321\315\322\323\217@\324\325\315\326\"!A\324\325\315\327\"\206FB\205F\330 \321B#C\324\325\315\331\332#!DE\203_\333 \202f\334 \206f\335 F\336 G\325\315\337\"\211H\205z\340H!H\341I\315\211JK\342L!\203\237\316\225b\210\317\343!M\344\345M\"?\202\322e\nNZ]\n{O\344\346\"\203\273\315\347\350\321\315$\202\274M\344PO\"J\344QO\"K\351 RS\204\346J\204\346K\204\346\313\314\321\"\210T\203\372\352\315\353\354\f\"\"\203\372\313\314\321\"\210J\203R\203\f\355U>?\202\356U>?\203\313\314\321\"\210K\2038R\203+\355V>?\2020\356V>?\2038\313\314\321\"\210J\203A\357\202KK\203J\360\202K\361W\344X@\"\204_\344Y@\"\203h\347\341\321\211@$@\344\362\"\203\203\363\364\317\365\"\366\"A\367\317\343\"RZ\202\206\341ZA\206\215@A\315\370\371\217[H\316V\204\243\\\316V\203\310[@\203\310[A@\203\310\365[8\203\310\372\373AH\206\302\\#I\202\313\341I)\344]A\"\203\357\347\374\225\203\343\317\374A\"\202\350\317\343A\"\321\211A$AJ\203\372\375APAK\203\376APA\344\377\"\203<r^q\210\343\312O_\201`\316\343\201F\201aWFQ_%\210_\201aA\201b\261\210*\202\230\201c\372\201dWFP\201e\201f\"\201eM\201g #ZAC\203v\344\201hC\"\203v\201iCP\202w\341D\203\217\344\201hD\"\203\217\201jDP\202\220\341GI&\n!\210\315\207" [org-icalendar-verify-function save-match-data-internal pos ts tags inc org-agenda-skip match-data ((byte-code "\301\302\"\207" [save-match-data-internal set-match-data evaporate] 3)) outline-next-heading -1 throw :skip nil 0 match-string org-get-tags-at t (byte-code "\300\301\302!!\207" [org-icalendar-cleanup-string org-get-heading t] 3) ((error (throw :skip nil))) org-icalendar-cleanup-string org-entry-get "SUMMARY" "DESCRIPTION" org-get-entry "LOCATION" selective org-id-get-create org-id-get org-id-new org-export-get-categories "APPT_WARNTIME" string-to-number "" looking-at 1 string-match "[0-9]\\{1,2\\}:[0-9][0-9]" "[0-9]\\{1,2\\}:[0-9][0-9]-\\([0-9]\\{1,2\\}:[0-9][0-9]\\)" replace-match "\\1" org-get-todo-state delq mapcar #[(x) " \235\207" [x org-export-exclude-tags] 2] event-if-todo event-if-not-todo "DL-" "SC-" "TS-" ...] 13) | org-print-icalendar-entries(nil) | byte-code("\306!\210\307!q\210 \204$\310\n!\311\312!!\313Q\307\f!rq\210\314 \210)\206.\311\312!!\2119\203;\315! \203V\204[\316\211\203[\317 !\210\202[\317!\210\320 !\210 \203h!\203l \204\236 \203|\"\203|\321\322!\210\323 \210\324 \210q\210\325\326!\210\327 \210\325\330!\210\331\332!\203\236\247\203\236\333!\210)\306\207" [file combine dir buffer-file-name ical-file ical-buffer org-check-agenda-file org-get-agenda-file-buffer file-name-as-directory file-name-sans-extension file-name-nondirectory ".ics" erase-buffer symbol-name t org-start-icalendar-file org-print-icalendar-entries require org-bbdb org-bbdb-anniv-export-ical org-finish-icalendar-file run-hooks org-before-save-iCalendar-file-hook save-buffer org-after-save-iCalendar-file-hook boundp org-wait sit-for org-category category standard-output started org-icalendar-combined-name files org-icalendar-include-bbdb-anniversaries] 5) | org-export-icalendar(nil "/home/hoor/Desktop/Projects/plans/test.org") | org-export-icalendar-this-file() | call-interactively(org-export-icalendar-this-file record nil) | command-execute(org-export-icalendar-this-file record) | execute-extended-command(nil "org-export-icalendar-this-file") | call-interactively(execute-extended-command nil nil) `---- If I replace org-icalendar with the version that comes with my Emacs 24.1.50.1 everything works. Thanks, Charles -- "If you want to travel around the world and be invited to speak at a lot of different places, just write a Unix operating system." (By Linus Torvalds)