problem with polyphony

[Stefan Thomas]

Dear Lilypond-Users,
when I write something like the below quoted music I get lots of
error warning, but I dont know why. It must have to Do with the
polyphony and the voices, but I don't understand it.
Could You please support me?
Thanks,
Stefan

\version "2.11.34"
artianfang = {s8-. s8-.
s4-.\accent \repeat "unfold" 5 {s4-. } }
rechts = \relative c { \context Voice = "A" << {\clef bass  <bes e
a>8 \f\< <b es c'>
<c d b'> \ff\> r \repeat "unfold" 5 {<c d b'>  r} }
{ \artianfang } >> {<c d b'>8-. \p r <c d b'>8-. r | } }

links = \relative c  { \context Voice = "A" << {\artianfang } { \clef
bass <b, f'>8 <bes a'>
\repeat "unfold" 6 { <es aes>8 r } } >>
\context Voice = "A"  { <<  { \repeat "unfold" 3 { <es aes>8 r} <es
aes>8 <des bes'>8 |
        <d g>8 r <d g>8 r <d g>16 r32 f, }
        {\repeat "unfold" 3 {s4-.} s8-.\f s8-.
s4-. s-. s16.-. s32\ff } >> }
{ cis'8~
\voiceOne
<< {cis4~ cis2.} }
\context Voice ="zwo" {\voiceTwo \repeat "unfold" 3 { <a gis'>8-. r }
} >>

}

\score
{
<<      \new Staff = "rechts" \rechts
        \new Staff = "links"  \links  >>
  }
Stefan Thomas
Siebengebirgsallee 9
50939 Köln
Tel.Fax:0049(0)221/412529
mail: address@hidden