Align then rotate perpendicular ?

All,
Below is a snippet of code that I am using to align a block to a selected
object (i.e. line). However, I am trying to modify it so that the object is
set perpendicular to the selected line instead of perfectly aligned. I have
several options, including getting the angle of the selected line then
adding 90, etc., however, nothing seems to work.

*snippet*
(while (< INDEX LEN)
(setq EN2 (entget (ssname S INDEX)))
(if (= (cdr (assoc 0 EN2)) "LINE")
(setq PT3 (cdr (assoc 10 EN2))
PT4 (cdr (assoc 11 EN2))
DIST2 (distance PT3 PT4)
PT5 (polar PT3 ANG DIST2)
EN2 (subst (cons 11 PT5) (cons 11 PT4) EN2)
)
(setq EN2 (subst (cons '50 ANG) (assoc 50 EN2) EN2))
)
(entmod EN2)
(setq INDEX (1+ INDEX))
)

Any ideas ?

 

Try this:

*snippet*

(if (not (member "geom3d.arx" (arx)))
(arxload "geom3d.arx")
)
(setq ss (ssget)
oldec (getvar "CMDECHO")
osm (getvar "OSMODE")
); setq
(setvar "CMDECHO" 0)
(setvar "OSMODE" 1)
(setq pt1 (getpoint "\nSpecify first point on object axis: ")
pt2 (getpoint "\nSpecify second point on object axis: ")
pt3 (getpoint "\nSpecify first point of the vector: ")
pt4 (getpoint "\nSpecify second point of the vector: ")
); setq
(setvar "OSMODE" 0)
(align ss pt1 pt3
pt2 pt4 "" "n")
(command "_.MOVE" (ssname ss 0) "" pt3 pt1)
(setvar "OSMODE" osm)
(setvar "CMDECHO" oldec)
(princ)