Thank you for reaching out. Could you please let us know the exact error message displayed? Kindly attach a screenshot so we can review it more accurately.
Yes, when installing the D5 LiveSync plugin, you must also have the D5 Render application installed on your computer. The LiveSync plugin serves as a bridge between your modeling software (Revit or 3ds Max) and the D5 Render application, where the synced model is opened and edited.