It's a bit far-fetched, but imagine this situation: You agreed to meet your friends at your favourite hospoda on Friday evening. Instead, you went there on Thursday evening, not realizing the day. The pub is empty, none of your friends in sight. You say to yourself '****, wrong evening!' and then you go and still have some beer. :)
(Well, you probably say something completely different, but for the sake of this sentence...)
Špatný večer can also mean 'bad evening' like Měl jsem špatný večer. = 'I've had a bad evening.' Who knows, maybe that was the intention behind this sentence and the authors just had a špatný večer when creating it. ;)
"Wrong evening" does not in fact make much sense for the translation, "bad evening" would be a much better one.
Only situation I can imagine "špatný večer" having the meaning of wrong would be in "I arrived at the airport on wrong evening -- the flight was scheduled for Friday but I arrived on Saturday" (which actually happened to me recently ;)