Hah, looks like someone really stole his old Bank Notes and replaced them by new ones! At least, the last hint suggests something like this.
But what now? What could the hint mean, when it was talking about "one single fail"? Let's have a look around...
Wait - something looks fishy there (if you'll excuse the pun). And it even has an engraving: "liaF regiznie nie", which roughly translates to "liaf elgnis eno".
Yes, yes, I know. It sounds a bit gibberish, but trust me. I am fluent in reading backwards.
So, where could the next hint be hidden? Oh, I know! It sure has to be on the bottom. Hints always are on the bottom of things.