[R-sig-Geo] raster: cannot extract object from list

[Agustin Lobo]

A function of mine outputs several raster objects in a list "l":
> class(l$lisaobsv)
[1] "RasterLayer"
attr(,"package")
[1] "raster"

But by some reason I get this weird error:
> a = l$lisaobsv
Error in slot(x, slotname) :
  no slot of name "z" for this object of class "RasterLayer"
Calls: <Anonymous> -> lapply -> FUN -> slot -> .Call
Warning message:
In .rk.get.structure.global("a") : failure to get object a

Is this a bug or is there an special way to extract raster objects from a list?

Thanks

Agus

> sessionInfo()
R version 2.13.0 (2011-04-13)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8          LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8           LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=en_US.UTF-8       LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=en_US.UTF-8          LC_NAME=en_US.UTF-8
 [9] LC_ADDRESS=en_US.UTF-8        LC_TELEPHONE=en_US.UTF-8
[11] LC_MEASUREMENT=en_US.UTF-8    LC_IDENTIFICATION=en_US.UTF-8

attached base packages:
[1] grid      stats     graphics  grDevices utils     datasets  methods
[8] base

other attached packages:
 [1] rgdal_0.6-33  geoR_1.6-27   plotrix_3.2-2 ggplot2_0.8.9 proto_0.3-8
 [6] reshape_0.8.4 plyr_1.4      raster_1.8-40 sp_0.9-76     rkward_0.5.6

loaded via a namespace (and not attached):
[1] lattice_0.19-26 tools_2.13.0