[求助]：Block....Redefine it? [Yes/No] <N>: 不見了

urdiafa

已寫一段程式如下
(if (= (tblsearch "block" blkna) nil)
   (command "block" blkna po ssent1 "")
    (command "block" blkna "y" po ssent1 "")
  );if
若block若存在,照理講應要執行 (command "block" blkna "y" po ssent1 ""),去蓋過已存在的block,
本來運做的很好,但最近突然有錯誤訊息,

Invalid point.
Quit action:Specify insertion base point:

即已存在block,卻執行
(command "block" blkna po ssent1 "")的狀況,我在command下測試

Command: (tblsearch "block" "in0_7")
((0 . "BLOCK") (2 . "in0_7") (70 . 0) (10 0.0 0.0 0.0) (-2 . <Entity name:
7ec98950>))

Command: -block
Enter block name or [?]: in0_7
Specify insertion base point:
Select objects:

這"in0_7" block已經存在,照理講要有下面訊息
Block "in0_7" already exists. Redefine it? [Yes/No] <N>:  
卻沒出現

很奇怪,程式已運行多年,怎會突然如此?我用acad2002,後我用acad2005測試也一樣,沒出現
Block "in0_7" already exists. Redefine it? [Yes/No] <N>:  

不知那位高手可指點一下?

Underway

查一下 Expert 系统变数

urdiafa

謝謝Underway,滿心感謝