use Win32::OLE qw(in with);
...
$Excel = Win32::OLE->new('Excel.Application', 'Quit');
$Excel->{Visible} = $vttrue;
$oBook = $Excel->Workbooks->Open("wishyouwerehere.xls");
...
if ($oBook->VBProject->{Protection} == 1)
{
$Excel->VBE->CommandBars->FindControl({ID=>2578})->Execute;
$Excel->SendKeys ($pass);
$Excel->SendKeys ("{ENTER}");
$Excel->SendKeys ("{ESC}"); 
sleep(1);
}
...