Adding reverse spring

[Edson Alves]

Hi. 

I trying write a 5 voice score, but im getting the follow error: 

Calculating line breaks... 
programming error: adding reverse spring, setting to unit 
continuing, cross fingers 

How i can fix it? 

Bellow the main .ly file 

-------------------------------------------------- 
\include "solo.ly" 
\include "soprano.ly" 
\include "contralto.ly" 
\include "tenor.ly" 
\include "baixo.ly" 

\version "2.6.3" 

\header { 
        title = "Misericórdia" 
} 

\score { 
        << 
        \new Staff { 
                \set Staff.instrument = "Solo" 
                \Solo 
        } 

        \new Staff { 
                \set Staff.instrument = "Soprano" 
                \Soprano 
        } 

        \new Staff { 
                \set Staff.instrument = "Alto" 
                \Contralto 
        } 

        \new Staff { 
                \set Staff.instrument = "Tenor" 
                \Tenor 
        } 

        \new Staff { 
                \set Staff.instrument = "Baixo" 
                \Baixo 
        } 
        >> 

        \layout {} 
        \midi {\tempo 4 = 80} 
} 

------------------------------------------------------ 

Thanks for attention. 

Edson