$ie->getTextBox(' name:', 'ctl00$ContentPlac eHolderContent $FileUpload_opfFile')->SetValue('C :/test/9780547076034NIMAS.opf'); 
$ie->WaitforDone;

##</code><code>##

$ie->getTextBox('name:', 'ctl00$ContentPlaceHolderContent$FileUpload_opfFile')->SetValue('C:\test\9780547076034NIMAS.opf');

$ie->getTextBox('name:', 'ctl00$ContentPlaceHolderContent$FileUpload_opfFile')->SetValue('C:/test/9780547076034NIMAS.opf');

$ie->getTextBox('name:', 'ctl00$ContentPlaceHolderContent$FileUpload_opfFile')->SetValue('C:\\test\\9780547076034NIMAS.opf');

....