I didn't notice this before, but take a look at these two lines:

wsLastRows(iCtr) = .Cells(1, .Columns.Count).End(xlToLeft).Column
wsLastCols(iCtr) = .Cells(.Rows.Count, "A").End(xlUp).Row

Do you see anything wrong?

Scroll down for an answer
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wsLastRows(iCtr) = .Cells(1, .Columns.Count).End(xlToLeft).Column
wsLastCols(iCtr) = .Cells(.Rows.Count, "A").End(xlUp).Row

You're putting a column number in a "row" variable and a row number in a "col"
variable. If the lastrow is greater than 256, then when you refer to that as a
column, you'll get an error.

wsLastCols(iCtr) = .Cells(1, .Columns.Count).End(xlToLeft).Column
wsLastRows(iCtr) = .Cells(.Rows.Count, "A").End(xlUp).Row

<<snipped