Programing error significance

[Karim Haddad]

Hello dear all,

Have you met this error message, and if yes, what does it really mean ?

Interpreting music...
Interpreting music...[8][16]
Preprocessing graphical objects...
programming error: My pure_y_common is a VerticalAlignment, which might contain 
several staves.
continuing, cross fingers
....
At first, it doesn't seem an error since the score compiles apparently well. 
Sorry i can't send it because i couldn't have the error in a small example.
Some info : it is a Piano score and i am using change Staff command (maybe it 
is related).

And if no, how can i debug my score ? any tips are welcome. I will try to do by 
removing extra "features" and see. If i can get to know what's causing it, will 
let you know.

Thanx
and best to you all

-- 
Karim Haddad