Translating languages is a very complex task. The translator works best when the text you wish to translate uses proper grammar. Slang, misspelled words, poorly placed punctuation, etc. can all cause a page to be translated incorrectly. Also the more translations a piece of text goes through, the further the resulting meaning will be from the original. So you will not necessarily get a good idea of the quality of a translation by translating the translated text.
Machine translation produces reasonable results in many cases.
But you should not rely on it. As in other areas of life, honesty pays. If you want to use a translated text always acknowledge the translator, and append or reference the original text. This will put the translation into the right context and will help you avoid embarrassing misunderstandings. Try news articles.