why is PHP/HTML file upload not working? -

i intend re-use code on http://www.w3schools.com/php/php_file_upload.asp create form allows file uploads. have used code on w3schools is(if copy-pasted it). when run error

"file image - image/jpeg.sorry, there error uploading file"

i'm running ubuntu 12.04 apache2 , php.ini settings upload set correctly allow file uploads