If you call "C-c C-c" within a table to align it, and point happens to be on a horizontal rule, it throws an error that originates in org-element-context.
The let at the top of that function sets "type" to 'table-row, and "element" to: (table-row (:type rule :begin XX :end XX :contents-begin nil :contents-end nil etc...)) Then on line 4749 comes: (and (memq type '(paragraph table-row verse-block)) (let ((cbeg (org-element-property :contents-begin element)) (cend (org-element-property :contents-end element))) (and (>= origin cbeg) (<= origin cend) (progn (goto-char cbeg) (setq end cend))))) "cbeg" and "cend" are nil, and strenuously object to being compared using >= or <=. I'm not sure what the context of a table rule ought to be, but it will need to be something with a non-nil :contents-begin value, since that gets called in `org-ctrl-c-ctrl-c' as well. Hope that's enough info... Eric