what size drive u using? the manual doesn't say what capacity drive it could handle but it must be fat16 fat32 or ntfs format
test the usb port out using a small usb stick to see if it isn't already working
in case you don't have its manual get it here ( http://www.samsung.com/au/support/model/UA40D5000PMXXY-downloads ) for English one find page 105 starts the bit about connecting usb and using