Here is the content of my org file:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >
> * Test                                >
>   |     | A | B |                     >
>   |-----+---+---|                     >
>   | com | 1 | 2 |                     >
>   | org | 3 | 4 |                     >
>                                       >
>   Some math formulae:                 >
>                                       >
>   y = x_1^2 + x_2^2                   >
>                                       >
>   y^2 = 2x^2 + 1                      >
>                                       >
>   z_2 = x_1 + x_2 + 2 (y_1 + y_2 + r) >
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >

Then I press C-c C-e l, I get the debug back-trace:

Debugger entered--Lisp error: (wrong-type-argument arrayp nil)
  replace-regexp-in-string("||" "|" nil)
  org-export-latex-tables(t)
  org-export-latex-content(#("\n  |     | A | B |\n  |-----+---+---|\n  | com | 1 | 2 |\n  | org | 3 | 4 |\n\n  Some math formulae:\n\n  y = x_1^2 + x_2^2\n\n  y^2 = 2x^2 + 1\n\n  z_2 = x_1 + x_2 + 2 (y_1 + y_2 + r)\n\n\n" 0 1 (fontified nil) 1 3 (fontified nil org-caption nil org-attributes nil org-label nil) 3 5 (fontified nil org-caption nil org-attributes nil org-label nil) 5 6 (fontified nil hilit-chg hilit-chg org-caption nil org-attributes nil org-label nil) 6 7 (fontified nil hilit-chg hilit-chg org-caption nil org-attributes nil org-label nil) 7 8 (fontified nil hilit-chg hilit-chg org-caption nil org-attributes nil org-label nil) 8 9 (fontified nil hilit-chg hilit-chg org-caption nil org-attributes nil org-label nil) 9 10 (fontified nil hilit-chg hilit-chg org-caption nil org-attributes nil org-label nil) 10 18 (fontified nil org-caption nil org-attributes nil org-label nil) 18 19 (fontified nil) 19 21 (fontified nil) 21 36 (fontified nil) 36 37 (fontified nil) 37 39 (fontified nil org-caption nil org-attributes nil org-label nil) 39 54 (fontified nil org-caption nil org-attributes nil org-label nil) 54 55 (fontified nil) 55 57 (fontified nil org-caption nil org-attributes nil org-label nil) 57 72 (fontified nil org-caption nil org-attributes nil org-label nil) 72 117 (fontified nil) 117 174 (fontified nil) 174 175 (fontified nil) 175 176 (fontified nil)))
  org-export-latex-subcontent(((pos . 2) (level . 1) (occur . 1) (heading . #(" Test " 1 2 ... 2 5 ...)) (content . #("\n  |     | A | B |\n  |-----+---+---|\n  | com | 1 | 2 |\n  | org | 3 | 4 |\n\n  Some math formulae:\n\n  y = x_1^2 + x_2^2\n\n  y^2 = 2x^2 + 1\n\n  z_2 = x_1 + x_2 + 2 (y_1 + y_2 + r)\n\n\n" 0 1 ... 1 3 ... 3 5 ... 5 6 ... 6 7 ... 7 8 ... 8 9 ... 9 10 ... 10 18 ... 18 19 ... 19 21 ... 21 36 ... 36 37 ... 37 39 ... 39 54 ... 54 55 ... 55 57 ... 57 72 ... 72 117 ... 117 174 ... 174 175 ... 175 176 ...)) (subcontent)) t)
  #[(x) "Â	\"‡" [x num org-export-latex-subcontent] 3](((pos . 2) (level . 1) (occur . 1) (heading . #(" Test " 1 2 ... 2 5 ...)) (content . #("\n  |     | A | B |\n  |-----+---+---|\n  | com | 1 | 2 |\n  | org | 3 | 4 |\n\n  Some math formulae:\n\n  y = x_1^2 + x_2^2\n\n  y^2 = 2x^2 + 1\n\n  z_2 = x_1 + x_2 + 2 (y_1 + y_2 + r)\n\n\n" 0 1 ... 1 3 ... 3 5 ... 5 6 ... 6 7 ... 7 8 ... 8 9 ... 9 10 ... 10 18 ... 18 19 ... 19 21 ... 21 36 ... 36 37 ... 37 39 ... 39 54 ... 54 55 ... 55 57 ... 57 72 ... 72 117 ... 117 174 ... 174 175 ... 175 176 ...)) (subcontent)))
  mapc(#[(x) "Â	\"‡" [x num org-export-latex-subcontent] 3] (((pos . 2) (level . 1) (occur . 1) (heading . #(" Test " 1 2 ... 2 5 ...)) (content . #("\n  |     | A | B |\n  |-----+---+---|\n  | com | 1 | 2 |\n  | org | 3 | 4 |\n\n  Some math formulae:\n\n  y = x_1^2 + x_2^2\n\n  y^2 = 2x^2 + 1\n\n  z_2 = x_1 + x_2 + 2 (y_1 + y_2 + r)\n\n\n" 0 1 ... 1 3 ... 3 5 ... 5 6 ... 6 7 ... 7 8 ... 8 9 ... 9 10 ... 10 18 ... 18 19 ... 19 21 ... 21 36 ... 36 37 ... 37 39 ... 39 54 ... 54 55 ... 55 57 ... 57 72 ... 72 117 ... 117 174 ... 174 175 ... 175 176 ...)) (subcontent))))
  org-export-latex-sub((((pos . 2) (level . 1) (occur . 1) (heading . #(" Test " 1 2 ... 2 5 ...)) (content . #("\n  |     | A | B |\n  |-----+---+---|\n  | com | 1 | 2 |\n  | org | 3 | 4 |\n\n  Some math formulae:\n\n  y = x_1^2 + x_2^2\n\n  y^2 = 2x^2 + 1\n\n  z_2 = x_1 + x_2 + 2 (y_1 + y_2 + r)\n\n\n" 0 1 ... 1 3 ... 3 5 ... 5 6 ... 6 7 ... 7 8 ... 8 9 ... 9 10 ... 10 18 ... 18 19 ... 19 21 ... 21 36 ... 36 37 ... 37 39 ... 39 54 ... 54 55 ... 55 57 ... 57 72 ... 72 117 ... 117 174 ... 174 175 ... 175 176 ...)) (subcontent))))
  org-export-latex-global((((... ... ... ... ... ...))))
  org-export-as-latex(nil)
  call-interactively(org-export-as-latex)
  org-export(nil)
  call-interactively(org-export nil nil)