这个代码哪里错啦？请大虾们回答。

Question

Dim str1 As String
Private Sub Command1_Click()
Open App.Path & "/JFD0275(COS).txt" For Input As #1

Do While Not EOF(1)
Line Input #1, str1
If find = " 51 " Then
Mid(str1, 6, 7) = str1
s = str1
Open App.Path & "\ 转换文件.txt " For Output As #2 '不能循环打开文件，放在循环体外部

Print #2, m '文件号要带"#"号
Close #2
MsgBox "提取成功"
End If
Loop

End Sub

Answer 1

Dim str1 As String
Private Sub Command1_Click()
Open App.Path & "/JFD0275(COS).txt" For Input As #1
Open App.Path & "\ 转换文件.txt " For Output As #2 '不能循环打开文件，放在循环体外部

Do While Not EOF(1)
Line Input #1, str1
If find = " 51 " Then
Mid(str1, 6, 7) = str1 '这句是要取出Str1,从第六个开始的7个字符么，并赋值给str1？那该倒过来写啊，不明白
s = str1

Print #2, m '写入了一个无关的量M
End If
Loop

Close #2
Close #1

MsgBox "提取成功"
End Sub