Oh, you're not in America, my apologies. Yeah, the law is different in different places (with, for example, Article 17 floatin' around in the EU placing copyright adherence on the shoulders on the webhosts along with those uploading the material themselves). Well, one bright side with all y'all people in Europe, Article 17 is something that you wouldn't need to concern yourself with, unless you were a web host, so if for example you had an arrangement posted on OCR and the copyright holder had issue with it that would become OCR's problem and not necessarily yours. It's a part of the whole non-exclusive publishing agreement you (supposedly) agree with when you send stuff to us, after all.
I did a touch of homework on how copyright works in the EU. They establish a few exceptions to copyright laws, which unfortunately does not include artistic interpretation. However, they DO allow each country to include their own separate exceptions to copyright law, of which in the Netherlands (where you're from, I believe) they include another exception saying something altered for artistic purposes (like, say, arranging VG music) and distributed shall not be considered a violation of copyright law, unless the original artist explicitly pursues the artist (and now distributor, under Article 13) staking claim to their work's copyright claim.
So for you, I believe you're legally in the clear, if you want to go arrangin' VG music, as long as the original artist doesn't come after you themselves. Hope that helps!