>Can anyone tell me the property (if it exists) for the number of the last occupied line/row in a spreadsheet. I am thinking of something like oSheet.numberoflines, where oSheet is an object reference to the active sheet.

Take a look on UsedRange property of WorkSheet. I think, you can get the number of the last occupied row as
oSheet.UsedRange.Row + oSheet.UsedRange.Rows.Count - 1