Try
your-buggy-line #num26 of code, here
Except
on E: EOutOfRange do Application.processmessages; (* <-- you set a breakpoint there, and you'll inspect your numerical variables, i, strings[j], ...,
which are used by your line #num26, and understand the one that exceeds its boundary.
Once the bug will be fixed, you'll delete the try...except *)
end;