use diagnostics;
if( my $textbox = $ie->getTextBox('name:', 'ctl00$ContentPlaceHolderContent$FileUpload_opfFile') ) {
    #Okay, now see if we can set the value
    if( $textbox->SetValue('C:\\test\\9780547076034NIMAS.opf') ) {
        print "it should work\n";
    } else {
        print "could not set the value\n";
    }
} else {
    print "could not get the text box\n";
}