请教VB的这段代码，下标越界，看不出问题出在哪里？多谢了

Private Sub Command1_Click()
Open "d:\23.txt" For Input As #1 '程序路径下的data.txt文件

Dim X(), Y() As String

MSFlexGrid1.Cols = 3
MSFlexGrid1.TextMatrix(0, 1) = "年份"
MSFlexGrid1.TextMatrix(0, 2) = "月均流量"
Do While Not EOF(1)
Line Input #1, tmp
If tmp <> "" Then
arr = Split(tmp, " ") '这里是以空格为分隔的，如果是逗号就用split(str,",")
If UBound(arr) > 0 Then
n = n + 1
ReDim Preserve Y(n - 1)
ReDim Preserve X(n - 1)
Y(n - 1) = arr(0)
X(n - 1) = arr(1)
MSFlexGrid1.TextMatrix(n, 1) = arr(0)
MSFlexGrid1.TextMatrix(n, 2) = arr(1)
MSFlexGrid1.AddItem ""
End If
End If
Loop
Close #1
End Sub
这是读取数据，储存在X()中的数据下面计算会用到，下面的计算代码：
Private Sub Command2_Click()
Dim R1() As String, R2() As Single