Well... I kept playing with this. I was finally able to make it work
if I inserted the following "selection" commands before the End Loop
command.

.....
'Select cell A1 of the Data worksheet (to restart back to the beginning
of the loop):
Sheets("Data").Select
Range("A1").Select
Loop

I'm not sure why this works... why would you need to select the data
worksheet in order to restart the macro?

Thanks,
Jessi