Fetch the row count in DDT driver

There's no method for row count, in DDTDriver Object Properties.

Use Working With Excel Files via COM instead.

Yes. See https://learn.microsoft.com/en-us/office/vba/api/excel.worksheet

Look at the code examples, and the spelling.

If you do an internet search, there will be plenty of examples on how to select a worksheet by name

Are you still having issues with Excel? Or is it working now with Excel via COM?

Note, I tend to refer to e.g. https://learn.microsoft.com/en-us/office/vba/api/excel.worksheet as majority of the functions are still applicable, and the coding examples I can "translate" to another language.

But it's only an issue with your machine? 

Do you have Microsoft Office 12.0 Access Database Engine OLE DB Provider installed on your machine? You can get it via Microsoft Access Database Engine 2010 Redistributable (32-bit or 64-bit installation package). It's a requirement when working with Excel Data Connectivity.

The System Requirements explains the requirements for Excel.