Transfer data from multiple workbooks to master workbook automatically

Hi,
I have multiple workbooks with a worksheet in each workbook with the same number of columns but different data entered. I would like to merge the multiple workbooks into one worksheet in a master workbook and have it update automatically when open.

I started by copying vba code into a module and updated it with the pertinent information (or so I think as I am new to this). I keep getting a run-time error 424 object required.
The line that is highlighted after debugging is:
erow = Sheet1.Cells(Rows.Count, 1).End(xlUp).Offset(1, 0).Row

Would anyone be able to look at my vba code and see where I went wrong. I have been going over this for a few days now and can't figure it out.

I am attaching some sample logbooks and the master logbook that has the vba code as samples.

Thanks in advance.
Lin