Hello Chang Hum,

I have seen a few things that are plain wrong and others that sound or look weird. However, without the reference text, it is, at least in some cases, hard to suggest/change something. If the reference text is available in English, we might be able to help you.
However, if you want a professionally looking translation, you will either need a lot of luck regarding the person doing it for free, or you have to offer a reward for the work.