Hi Grover,
I came across your topic when I was wondering the same and I just solved it.
Go To:
Settings > Store
Then Click on the payments tab.
If you roll over paypal on the left hand side, you will see a small “edit” appear in the same row on the right hand side. click this “edit” and a small window will pop up on the right hand side. here you can add you paypal email address and the check out should now work.
I hope this helps ??
