Lilypond doesn't like BOM if a name is the first thing in the document.

[Decade]

> I'm not top posting.

(This doesn't work so well without file attachments.)

stuff={
  a
}
\score {
  \new Staff \stuff
}
\version "2.10.20"

If you save that in Microsoft Notepad's default encoding, it works. But if you 
save it in UTF-8 (because lyrics are in foreign languages), Notepad inserts a 
BOM, and Lilypond fails to parse it. The beginning identifier "stuff" becomes 
$EFBBBF"stuff" and the later reference can't find it:
error: unknown escaped string: `\stuff'

If the document starts with a special character, such as '\' or CRLF, then the 
Unicode BOF doesn't cause problems.