这是什么情况

command2的代码出了什么错，一运行就出现弹窗说子程序或函数未定义
Private Sub Command2_Click()
Dim x(1 To 5, 1 To 5) As Integer
For i = 1 To 5
Print Tab(8);
For j = 1 To i
a(i, j) = 5 * (i - 1) + j
Print a(i, j);
Next j
Next i
End Sub