To make the holes you need means that it’s doing move/copy on three different planes at the same time. I think you can only do one plane at a time. An alternative is to leave the hole as group, make the duplicates, and then do a big intersects with model to create the holes. But trying that locked up SketchUp.
So I tried a different approach. I removed your first attempt copy, exploded everything, then did a move/copy of just the outer ring (I used move/copy for one position, then typed 7x return, to get the other columns, then I selected one row and move/copy, 7x to get all the rows).
I did a push pull to get the initial sunk amount (63 times), and then did another move/copy 7x, columns, then rows, to get the inner hole. Lastly, I did 63 more push/pulls to get the hole through to the back.
I feel sure there’s an easier way, but I’ve attached what I had at that point.
Wasteboard With Holes.zip (2.0 MB)