[Koha] create barcode with item number "Error to open pdf file"

when i am creating bar code label for books with item number pdf file give "error to open file" what is my mistake could any one give steps koha 3.0 to create barcode? thank you -- ---------------------------- Y.Yatheesh babu Librarian Shri Shakti College of Hotel Management Venus Plaza Begumpet Hyderabad-500 016 09966178388