$Win32::OLE::Warn = 3;                     # die ( UGLY ) on errors...
my $Excel =  Win32::OLE->new('Excel.Application', 'Quit');
my $Book = $Excel->Workbooks->Open($FN);
my $Sheet = $Book->Worksheets(1);         # select worksheet number 1

$LastCol = $Sheet->UsedRange->Find({What=>"*",
        SearchDirection=>xlPrevious,
        SearchOrder=>xlByColumns})->{Column};