\overrideProperty throws an error

[Kieren MacMillan]

[ Lilypond 2.9.14 ]

Hello, all --

Does anyone recognize this error, or is this a known issue in the  
current build:

    warning: Unknown event class apply-output-event                     
                        \overrideProperty  
#"Score.NonMusicalPaperColumn"

As a result of this issue, I'm not able to adjust the fixed-alignment  
distance of my PianoStaffs.

Thanks,
Kieren.