Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  string-match("^file:\(.+\)::" nil)
  #f(compiled-function (l) #<bytecode 0x411d16ed>)((nil ""))
  mapcar(#f(compiled-function (l) #<bytecode 0x411d16ed>) (("file:~/Pending/org/gtd/privat.org::*Brackweder Baugenossenschaft" "Brackweder Baugenossenschaft") (#("file:/tmp/test.txt::Hello" 20 25 (fontified t)) nil) ("file:~/Pending/org/gtd/privat.org::*Foci" "Foci") (#("file:~/Pending/org/gtd/dev.org::as" 32 34 (wrap-prefix #("        " 0 7 (face org-indent) 7 8 (face org-indent)) line-prefix #("        " 0 7 (face org-indent)) fontified t)) "transition to CalendarView framework") ("file:~/Pending/org/gtd/dev.org::*add app icon" "add app icon") (nil "") (nil "")))
  org-link-fontify-links-to-this-file()
  org-insert-link(nil)
  funcall-interactively(org-insert-link nil)
  call-interactively(org-insert-link nil nil)
  command-execute(org-insert-link)