Try this event handler. This assumes the 'first column' in your workbook is column 'A'.
Private Sub UserForm_Initialize()
Dim LastRow
LastRow = ActiveSheet.Range("A" & Rows.Count).End(xlUp).Row
If IsNumeric(ActiveSheet.Range("A" & LastRow)) Then
ActiveSheet.Range("A" & LastRow).Offset(1).Value = _
ActiveSheet.Range("A" & LastRow).Value + 1
Else
ActiveSheet.Range("A" & LastRow).Offset(1) = 1
End If
LastRow = ActiveSheet.Range("A" & Rows.Count).End(xlUp).Row
Me.formnumberlabel.Caption = ActiveSheet.Range("A" & LastRow)
End Sub
This assumes that there is a column header in cell A1. I would suggest that you specify the worksheet name instead of 'ActiveSheet' in the code above. If you were to call your userform from another worksheet, bad things could happen. For example, if your worksheet is named "New Entry", change the lines thusly:
Private Sub UserForm_Initialize()
Dim LastRow
LastRow = Sheets("New Entry").Range("A" & Rows.Count).End(xlUp).Row
If IsNumeric( Sheets("New Entry").Range("A" & LastRow)) Then
Sheets("New Entry").Range("A" & LastRow).Offset(1).Value = _
Sheets("New Entry").Range("A" & LastRow).Value + 1
Else
Sheets("New Entry").Range("A" & LastRow).Offset(1) = 1
End If
LastRow = Sheets("New Entry"). Range("A" & Rows.Count).End(xlUp).Row
Me.formnumberlabel.Caption = Sheets("New Entry").Range("A" & LastRow)
End Sub