error: no rhythmic group to end

[James E. Bailey]

I'm a little puzzled by this. I get the error: no rhythmic group to  
end, but the output looks fine. Should I worry?
\version "2.11.58"
global = { \time 6/4 s1. }
sopranosoloMusic = \relative f'' { r4 es b(~ \times 2/3 {b8[ c d]}  
\times 2/3 {es4) c b} }
sopranosoloWords =\lyricmode {
   my soul has grown
}
sopranosoloDynamics = { s4 s2.^\< \times 2/3 {s4 s s\!} }
\score {
   \new ChoirStaff <<
      \new Staff \context Voice = "sopranosolo" << \global  
\sopranosoloMusic \sopranosoloDynamics >>
      \new Lyrics \lyricsto "sopranosolo" \sopranosoloWords
   >>
   \layout { \context { \Staff \remove "Time_signature_engraver" } }
}