I get the same thing. You hit the option for perfect singing and it just says the word error and nothing happens. Also I tired the dancing option and it activated but when dancing I tried 2 songs and failed both with no score change from the trainer. Can probably provide a save file if I know where they are.
A save game with exact and easily repeatable instructions is always appreciated. Please look up this location here -> C:\Program Files (x86)\steam\userdata\number\638970\remote\ for a save file.
You need to zip/rar/7z it before upload.