When I try and export the following code to beamer, using the C-c C-e l
b, it gives the error:

setq: Wrong type argument: arrayp, nil

example file that causes the error:

#+STARTUP: beamer
* Introduction                                                     
:B_frame:
  :PROPERTIES:
  :BEAMER_env: frame
  :END:
** Tools I looked at                                               
:B_frame:
   :PROPERTIES:
   :BEAMER_env: frame
   :END:
   + test

Let me know if you need any further info?

Emacs  : GNU Emacs 24.3.1 (x86_64-apple-darwin12.3.0, NS
apple-appkit-1187.37)
 of 2013-03-17 on tolkien.lan
Package: Org-mode version 8.2 (8.2-elpa @
/Users/jason/.emacs.d/elpa/org-20130919/)

current state:
==============
(setq
 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)
 outline-minor-mode-hook '(mediawiki-outline-magic-keys)
 org-latex-classes '(("beamer"
                     
"\\documentclass[presentation]{beamer}\n[DEFAULT-PACKAGES]\n[PACKAGES]\n[EXTRA]"
                      ("\\section{%s}" . "\\section*{%s}")
                      ("\\subsection{%s}" . "\\subsection*{%s}")
                      ("\\subsubsection{%s}" . "\\subsubsection*{%s}"))
                     ("article" "\\documentclass[11pt]{article}"
                      ("\\section{%s}" . "\\section*{%s}")
                      ("\\subsection{%s}" . "\\subsection*{%s}")
                      ("\\subsubsection{%s}" . "\\subsubsection*{%s}")
                      ("\\paragraph{%s}" . "\\paragraph*{%s}")
                      ("\\subparagraph{%s}" . "\\subparagraph*{%s}"))
                     ("report" "\\documentclass[11pt]{report}"
                      ("\\part{%s}" . "\\part*{%s}")
                      ("\\chapter{%s}" . "\\chapter*{%s}")
                      ("\\section{%s}" . "\\section*{%s}")
                      ("\\subsection{%s}" . "\\subsection*{%s}")
                      ("\\subsubsection{%s}" . "\\subsubsection*{%s}"))
                     ("book" "\\documentclass[11pt]{book}"
                      ("\\part{%s}" . "\\part*{%s}")
                      ("\\chapter{%s}" . "\\chapter*{%s}")
                      ("\\section{%s}" . "\\section*{%s}")
                      ("\\subsection{%s}" . "\\subsection*{%s}")
                      ("\\subsubsection{%s}" . "\\subsubsection*{%s}"))
                     )
 org-speed-command-hook '(org-speed-command-default-hook
                          org-babel-speed-command-hook)
 org-occur-hook '(org-first-headline-recenter)
 org-metaup-hook '(org-babel-load-in-session-maybe)
 org-confirm-shell-link-function 'yes-or-no-p
 org-latex-format-headline-function
'org-latex-format-headline-default-function
 org-default-notes-file "~/Dropbox/org/todo.org"
 org-after-todo-state-change-hook '(org-clock-out-if-current)
 org-src-mode-hook '(org-src-babel-configure-edit-buffer
                     org-src-mode-configure-edit-buffer)
 org-agenda-before-write-hook '(org-agenda-add-entry-text)
 org-babel-pre-tangle-hook '(save-buffer)
 org-mode-hook '((lambda nil
                  (org-add-hook (quote change-major-mode-hook)
                   (quote org-show-block-all) (quote append) (quote local))
                  )
                 (lambda nil
                  (org-add-hook (quote change-major-mode-hook)
                   (quote org-babel-show-result-all) (quote append)
                   (quote local))
                  )
                 org-babel-result-hide-spec org-babel-hide-all-hashes
                 (lambda nil (flyspell-mode -1)))
 org-refile-targets '((nil :maxlevel . 9) (org-agenda-files :maxlevel . 9))
 org-ctrl-c-ctrl-c-hook '(org-babel-hash-at-point
                          org-babel-execute-safely-maybe)
 org-directory "~/Dropbox/org"
 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-M-RET-may-split-line '((default))
 org-blank-before-new-entry nil
 org-confirm-elisp-link-function 'yes-or-no-p
 org-metadown-hook '(org-babel-pop-to-session-maybe)
 org-agenda-files '("~/Dropbox/org/todo.org" "~/Dropbox/org"
                    "~/Dropbox/org/todo.org")
 org-clock-out-hook '(org-clock-remove-empty-clock-drawer)
 )