grace notes cause extra bar to contain them

[Rob Canning]

hi,
not sure whats going on here...
if i isolate and render only one of the two staves then everything is 
fine but if i parse the .ly that contains two staves an extra bar gets 
created that contains the grace notes.
i cant figure out why...
here is the .ly
http://pastebin.com/m672b44fd
see first set of grace notes in the upper part.

any ideas why this is happening?
thanks
rob