求救！！！读取文件的一行后，无法对读取的字符串操作

shui_yan

(defun c:ofile()
  (setq file-path (findfile "bp.ini"))
  (setq point-f (open file-path "r"))
  (setq profile-list nil profile-table nil)
  (while (setq profile-list (read-line point-f))
   (setq stringlen (strlen profile-list))
   (setq num-test 1
  num-start nil
  char-len 0
  list-item nil
  new-profile-list nil)
   (while (<= num-test stringlen)   
    (setq char-test (subst profile-list num-test 1))  ；运行到这行后就跳出，提示“命令: ofile ; 错误: 参数类型错误: consp 1，这是什么问题呀？
    (if (= char-test "space")
      (setq num-test (1+ num-test))
      (progn
        (setq char-start num-test)
        (while (= char-test "space")
   (setq num-test (1+ num-test))
   (setq char-len (1+ char-len))
        )
        (setq list-item (subst profile-list num-test char-len))
        (setq new-profile-list (append new-profile-list (list list-item)))
      );end progn
     );end if    
    );end while   
    (setq profile-table (append profile-table (list new-profile-list)))
  )

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liums79

(setq char-test (subst profile-list num-test 1))  命令都是错的substr