Plot of POSIXct date vs numeric gives Error in cut.default ... cannot allocate vector

[PaulHurleyUK]

I'm having a problem producing a line plot using some data that is
POSIXct dates and numeric counts. When I try to plot it via ggplot2 I
get an error

> ggplot(foo, aes(x=Date, y=Count))+
+ geom_line()
Error in cut.default(unclass(x), unclass(breaks), labels = labels,
right = right, :
cannot allocate vector of length 1317423601
>
> ggplot(foo[2:349,], aes(x=Date, y=Count))+
+ geom_line()
Plot produced...

I posted the data in a stack overflow question if it helps (
http://stackoverflow.com/q/9621224/74658 )

This is R 2.14.1 and ggplot2 0.8.9.

Any ideas ??

Paul.