TickLabels is not a function, so don't use it like one.

$Excel->Selection->TickLabels({Font => {Size => 8}});
Should be (Untested!)
$Excel->Selection->TickLabels->Font->{Size} = 8;

This stuff is fundamental to using OLE from perl. You need to read the Win32::OLE docs as well as Excel's help file to help you understand how to translate from VB to perl.