EXPLANATION The main function of adverbs, adverbial phrases and adverbial clauses is to give more information about (i.e. to modify) verbs and adjectives. In the example above, the phrase by his parents is meant to modify told. Consequently, it needs to be placed as near as possible to told in order to avoid confusion. (Josh was told by his parents not selected for the team by his parents!)
Because adverbial information can be moved around in English sentences, such errors can occur fairly easily. The most common example of this is the placement of 'only', which is often misplaced. Take this sentence, for example: The day before the marathon, he only ran five kilometres. Because the modifier 'only' has been placed next to 'ran', it means that he only ran; he didn't cycle, swim or whatever. That is different from ... he ran only five kilometres (not, say, 10 kilometres). In other words, he had a light training session!