[FallenXxRaven]

Did you click off the FFR game screen before the arrows came? That will make your keystrokes not count. It may be a good idea to click on the black of the game screen before each song. I dunno if this is what you did, but I know I've accidently done this many many times.

You should also try other songs and see if its your keyboard or maybe that specific song. FFR is still reviving and bugs on specific songs aren't out of the question. If you only have that problem with that song, PM me what song it is and I'll check it out too.

You could also see if trying different keymapping changes anything. Try using WASD or something to see if that makes a difference.

I can't really think of much else, so I hope this helps in some way