Compiling usage-examples/example.ly gives errors

[Daniel Rosen]

When I try to compile usage-examples/example.ly, I get this log.

Making any one of the following changes allows the the file to compile error-free:

1. Commenting out the first two staves in the \score block.
2. Commenting out the third stave in the \score block.
3. Commenting out the barNumber parameter under \gridSetSegmentTemplate 4.