请问我下载的这个平行线中线在浩辰无法使用是什么原因？

;; pxxzx(平行线中线)
(defun c:pxxzx ()
(if (and (setq ss (ssget '((0 . "*LINE,ARC,CIRCLE,ELLIPSE"))))
(= (sslength ss) 2)
)
(progn
(setq s1 (ssname ss 0)
s2 (ssname ss 1)
p1 (vlax-curve-getStartPoint s1)
p2 (vlax-curve-getStartPoint s2)
pt (mapcar '(lambda (x y) (* (+ x y) 0.5)) p1 p2)
p1 (vlax-curve-getclosestpointto s1 pt)
dd (distance pt p1)
)
(command "offset" dd "")
(command "offset" "" (list s1 p1) pt "")
(command"chprop" (entlast) "" "c" 1 "")
)
)
(princ)
)