Is the money earned from translating promotional materials for "QuestNet" products unlawful, especially given the prior ignorance of the Sharia prohibitions related to network marketing upon which the company relies?

There is no harm in you benefiting from your earnings from translating the company's products, as long as there is no deception or fraud in the translation. However, you must refrain from working with it if its work is based on network marketing, due to the assistance it provides to falsehood. If its work is mixed and you can work in what is permissible, then there is no harm, but it is preferable to search for another job that is free from doubt.