哪位大哥大姐帮我看看，这程序哪里错了，十分感谢VB

Private MyArray(60) As Integer ✀设置全局数组变量Private Sub 开始_Click()停止.Enabled = True ✀停止按钮当前有效Dim a As IntegerRandomizes = 0For i = 1 To 60s = s + MyArray(i - 1)NextIf s < 3660 ThenDoa = Fix(Rnd * 60 + 1) ✀使用随机函数Loop While MyArray(a - 1) = 61 MyArray(a - 1) = 61抽取框.Text = a结果框.Text = ""LoopElseMsgBox ("抽取完毕！")DoEventsEnd IfEnd SubPrivate Sub 停止_Click()结果框.Text = 抽取框.Text已抽题目 = 已抽题目 + 抽取框 + "号题" + ","停止.Enabled = FalseEndEnd SubPrivate Sub 打开抽取的题目_Click()ActivePresentation.SlideShowWindow.View.GotoSlide (抽取框.Text + 1)End SubPrivate Sub 已抽题目_Change()End Sub 放各侠哥侠姐我是菜菜，从来没用过，救救我啊