That email/comment looks like nonsense. The English is lamentable and full of typos.
This Ray Rubyn is impossible to find on the internet.
In 2005 Flür spoke at the occasion of some 'Indie Awards' evening - which could indicate he might not even have a manager.
Rüdiger Plegge, however,
is a lawyer who represents people like Joe Cocker in copyright affairs.
I'd send him a note back.
[quote]
Sehr geehrter Herr Rubyn,
Nach Rücksprache mit meinem Rechstberater würde ich Sie gerne bitten so freundlich zu sein mir eine Indikation zu geben in welcher Hinsicht meine Veröffentlichung auf YouTube gegen deutsches und/oder internationales Recht verstösst.
Mit freundlichen Grüssen,
connellmcg (my acronym

)
[quote]
(After speaking to my legal advisor I would like to ask you to be so kind as to indicate in what way my publication violates German and/or international law.
with kind regards,)
He should be able to fire back a) a believable set of reasons why you violate the law and b) perfect German.