Royal, it does not currently work. However, it is mainly based on direct database functions, versus i-mscp hooks, so it is easier for me to make it work than the WHMCS one which is hooks-based and I have no idea how that's all working with the new version of i-mscp. that being said, HostBill is run by an insane person in Poland who keeps breaking EU law and changing prices and licensing every week, while being okay software, the modules don't get updates, and it has a very unstable future because the owner/main developer is a very unstable person with no business or legal sense. I advise against using it.
Also, he has now said that people that own HostBill after version 4.6.0 cannot have 3rd party modules, only modules that he creates. Which is completely against EU law, and likely why HostBill is saying it can't read the files, because he has put in ILLEGAL code to restrict it. So, you must wait until Kris (Chris) Pajak makes an i-MSCP module (never), or file an EU complaint and/or Polish lawsuit against him. But get your money back from that scumbag.