Unused Arguments error

[ultimatemegs]

require(timeline)
require(ggplot2)

example:

data(ww2)
timeline(ww2, ww2.events)
timeline(ww2, ww2.events, event.spots=2, event.label='', event.above=FALSE)

Error in timeline(ww2, ww2.events) : unused arguments (ww2, ww2.events)

This error occurs following the provided example code exactly having already installed - also appears to be occurring on the RShiny app. Same code was working last week...