making parts : specific number of measures per line?

[Molly Preston]

Hi again everyone,

I am trying the following for making 6 measures per line in the flute part.

layoutContent = {

     s1 *6 \break 

}

\score { 

\new Staff <<

   \new Voice { 

\fluteMusic

} 

    \new Voice  { 

\repeat unfold 20 { \layoutContent } 

   } 

>>

}

If i use the repeat unfold command I get an error that states

warning: forced break was overridden by some other event, should you be using bar checks?

What events override a forced break?

-Molly