Of course, you should always apply some error handling to your scripts as well. PHPExcel throws exceptions, so you can wrap all your code that accesses the library methods within Try/Catch blocks to trap for any problems that are encountered, and deal with them in an appropriate manner.
The PHPExcel Readers throw a PHPExcel_Reader_Exception.
$inputFileName = './sampleData/example-1.xls';
try {
/** Load $inputFileName to a PHPExcel Object **/
$objPHPExcel = PHPExcel_IOFactory::load($inputFileName);
} catch(PHPExcel_Reader_Exception $e) {
die('Error loading file: '.$e->getMessage());
}
See Examples/Reader/exampleReader16.php for a working example of this code.