Sideway Notes
If during the gameplay you get something like this:
then it means you picked wrong notes for your Frets on Fire version - you are using file note.dae meant for 1.1.324 on 1.2.451 or vice versa.
To fix it, simply download another note.dae, meant for your Frets on Fire version and replace it with the original. Search at the list of mods at the wiki or at the forum.