Import/Export tool

I just installed your Import/Export tool but I have no idea how to create XML file with all the data in excel sheet and upload the who products list to my shop. When I export, it works fine, but when I import, it thrown following fetal error

Fatal Error: Uncaught exception 'Exception' with message 'Could not open C:\WINDOWS\Temp\php8A3.tmp for reading! File does not exist.' in D:\hshome\c343706\shop.wecareindia.org\opencart\system\PHPExcel\Classes\PHPExcel\Reader\Excel2007.php:168 Stack trace: #0 D:\hshome\c343706\shop.wecareindia.org\opencart\system\PHPExcel\Classes\PHPExcel\IOFactory.php(269): PHPExcel_Reader_Excel2007->canRead('C:\WINDOWS\Temp...') #1 D:\hshome\c343706\shop.wecareindia.org\opencart\system\PHPExcel\Classes\PHPExcel\IOFactory.php(207): PHPExcel_IOFactory::createReaderForFile('C:\WINDOWS\Temp...') #2 D:\hshome\c343706\shop.wecareindia.org\opencart\admin\model\tool\export.php(1579): PHPExcel_IOFactory::identify('C:\WINDOWS\Temp...') #3 D:\hshome\c343706\shop.wecareindia.org\opencart\admin\controller\tool\export.php(13): ModelToolExport->upload('C:\WINDOWS\Temp...') #4 D:\hshome\c343706\shop.wecareindia.org\opencart\system\engine\front.php(47): ControllerToolExport->index() #5 D:\hshome\c343706\shop.wecareindia.org\opencart\system\engine\front.php(29): Front->execute(Array, Array) #6 D:\hshome\c343706\shop.wecareindia.org\opencart\admin\index.php(158): Front->dispatch(Object(Action)) #7 {main} thrown in D:\hshome\c343706\shop.wecareindia.org\opencart\system\PHPExcel\Classes\PHPExcel\Reader\Excel2007.php on line 168

Any help Please