Another bit of very poorly engineered software and hardware happened to me in the library today. They have machines allowing you to check out books yourself, without any assistance. Basically, the machine has a bar-code scanner and you first place your library card beneath it and are asked to enter your PIN (which handily is your birth date by default and can be read by all the library staff in clear text - I guess it keeps people from taking out books with a library card they found somewhere, though). Then you place the book on the machine, it reads the bar code, puts the book on you account and does whatever magnetic trickery they do to keep the alarm from going off when you leave. Repeat for all books, remove card, take receipt.
The 'enter-the-PIN' bit is where the bad engineering comes in: The keypad for entering the PIN is behind the bar-code scanner which kind-of sticks out of the machine. This way the keypad is hard to discover and even harder to use as you have to move around a bit to see the keys or at least see whether it's a telephone-style or a calculator-style keypad.
This is also where the bad softare engineering comes in. You'd thing that hardly anything can go wrong: It's a simple machine with a very limited interface. There are very few things the user can do wrong and there are instructions on how to place the card and books on the machine. So I entered my PIN and it said 'wrong PIN'. OK, I may have mistyped it, so I try again. Again it says 'wrong PIN'. Hm, try again - nope. Finally I asked the guy at the issue desk to check the card and it turned out it had expired (it's a card for life, no expiry date noted on it). Right, that explained why I couldn't take out books - but saying 'wrong PIN' in this situation is just bad software.
Renewed the card, entered the same PIN, took out the book, no problems.
Received data seems to be invalid. The wanted file does probably not exist or the guys at last.fm changed something.