Error creating GlobalSoilMap object (GSIF package)

Dear All,
I have been trying to follow this tutorial on 3D modelling of soil with the
GSIF package:
http://gsif.isric.org/doku.php?id=wiki:tutorial_eberg

(code on:
https://code.google.com/p/gsif/source/browse/trunk/eberg/tutorial_eberg.R)

When I get to creating a GlobalSoilMap object (line 181):

SNDMHT.gsm <- GlobalSoilMap(sd.ll, varname="SNDMHT", period=c("1999-02-01",
"2001-07-01"))

I get an error saying:
Error in GlobalSoilMap(sd.ll, varname = "SNDMHT", period = c("1999-02-01",
: unused argument (period = c("1999-02-01", "2001-07-01"))

I think the tutorial is quite old. I checked the help and then replaced
"period" for "TimeSpan". I now get the following error:
 Error in initialize(value, ...) :
  invalid name for slot of class "GlobalSoilMap": TimeSpan.begin


Here is some information on this function:

GlobalSoilMap function (obj, varname, TimeSpan = list(begin = Sys.Date()

- 1, end = Sys.Date())) { if (!class(obj) == "list") { stop("Object of
class 'list' required") } out = new("GlobalSoilMap", varname = varname,
TimeSpan.begin = TimeSpan, sd1 = as(obj[[1]], "SpatialPixelsDataFrame"),
sd2 = as(obj[[2]], "SpatialPixelsDataFrame"), sd3 = as(obj[[3]],
"SpatialPixelsDataFrame"), sd4 = as(obj[[4]], "SpatialPixelsDataFrame"),
sd5 = as(obj[[5]], "SpatialPixelsDataFrame"), sd6 = as(obj[[6]],
"SpatialPixelsDataFrame")) return(out)
}

Any ideas?
Thanks.

Ruth

        [[alternative HTML version deleted]]