DataSet - Dynamic DataTable (Table Adapter)

I want a dyanmic dataset that gets updated everytime someone imports a text file.
I inserted a blank dataset into my project.

I added a datatable (tbl_Invoices)
I then tried to add a Table Adapter to my (tbl_Invoices), but it's greyed out?
Why can't I create dymanic dataset, with a datatable, but can't add an Adpater?

See attached screen shot.

Thanks,
Mark
TableAdapter.jpg