Visual Basic - El subíndice está fuera del intervalo (Error 9) VBA 6

Option Explicit

Dim x(4) As Integer

Dim c As Integer

Dim y As Integer

Dim i As Integer

Private Sub Command1_Click()

For i = 0 To 4

List1.AddItem ("N" & i + 1 & "=" & x(i))

If i = 4 Then

Command2.Enabled = True

Command1.Enabled = False

End If

Next

c = 0

i = 0

End Sub

Private Sub Command2_Click()

If x(c) >= x(c + 1) Then

y = x(c)

x(c) = x(c + 1)

x(c + 1) = y

c = c + 1

Else

c = c + 1

End If

If c = 4 Then

i = i + 1

c = 0

End If

If i = 4 Then

For c = 0 To 4

List2.AddItem ("N" & c + 1 & "=" & x(c))

Next

End If

End Sub

Private Sub Text1_KeyPress(KeyAscii As Integer)

If KeyAscii = 13 Then

x(c) = Val(Text1.Text)

c = c + 1

Text1.Text = ""

If c = 5 Then

Text1.Enabled = False

Command1.Enabled = True

End If

End If

End Sub