All,
There has been some miscommunication on our part in regards to Jagex Accounts working with our Bot Manager. This is a video guide made by @Bjotorsflav showing you how to use Jagex accounts with our bot manager. If you've heard from someone that we don't support Jagex accounts, that is 100% wrong.
If any of you encounter the 'Failed to login to Jagex account for input string "Null"' error, please utilize Developer Version 2.16. This version now prompts for a Jagex verification code (which is sent to your email). Simply type it in, and voila, everything works smoothly.