Hi, i have bought the diva controller (the big one) and I've got this big problem, I've red that some people got this bug but the administrators didn't find any solution. So I will explain at the detail: when I hold two or three notes and then I want to press the square notes but it says ''worst'' and makes me fail every square note. Also when I want to do the quadruple bonus the same, error at the square. Please if anyone has had this problem and he/she had solved it please reply me, I've tried a lot of things but nothing works. And I've reinstalled the program several times but nothing :(

I don't know which one you bought, but it is controller button assignment problem.
Show me KHC\PPD\keyconfig.ini

So, the problem that you assign left to triangle and right to square.
You can not press left and right at the same time.(If you can't understand this meaning, launch gamepad option in windows and see what happens when you press left and right).
If your controller is the first model(price is about 30000yen), there is the toggle switch to change behavior left and right button.
If not, you must open controller and swap connection of lines as you need.