Win32::OLE, setting Excel font

I want to set a font in the entire Excel spreadsheet.  When I wun the code b
elow, I get the following error:

Can't call method "Font" without a package or object reference [line 4 below
]...

I havent' worked with the OLE API before, so I got this from some examples t
hat I saw:

my $Book = $xl->Workbooks->Add;
my $Sheet = $Book->Worksheets(1);
my $Selection = $Sheet->cells->select;
$Selection->Font->Name = 'Arial Unicode MS';

I interpret the error message to mean that 'Selection' is not an object.  Ho
w does one set the font?