spplot for raster not drawn

dear list
I want to display a time series of data using either spplot or levelplot to verify consistency in the raw images prior to processing (visual quality check)
to do this I am use spplot (or levelplot). This works up to 16 images, however if I want to see more I have to split the inputfiles and put them in  a loop. When the loop is executed, I can see the quartz window but the content is not shown. 
Does anyone have an idea how to solve this ?
See below for information on OS and versions + code

Thanks for help
Els


require(raster) #raster package = 1.9-5
require(rasterVis) #rasterVis = 0.10-4
setwd(outputdir)
#get all the inputdata
par(ask=T)
inputlist <- list.files(pattern="LSTDay")
datadisplay <- seq(1,length(inputlist),16)
datadisplay <- c(datadisplay,length(inputlist))
n <- length(datadisplay)-1
for (i in 1:n){
	input <- inputlist[datadisplay[i]:datadisplay[i+1]-1]
	images <- stack(inputlist)
	NAvalue(images)<-0
	#spplot(images,col.regions=terrain.colors(80)) # quartz is shown but remains empty
	levelplot(images,col.regions=terrain.colors(80)) # quartz is shown but remains empty
	hist(images,xlim=c(220*50,340*50),n=20) #histograms are displayed in quartz
}


$platform
[1] "i386-apple-darwin9.8.0"

$arch
[1] "i386"

$os
[1] "darwin9.8.0"

$system
[1] "i386, darwin9.8.0"

$status
[1] ""

$major
[1] "2"

$minor
[1] "13.1"

$year
[1] "2011"

$month
[1] "07"

$day
[1] "08"

$`svn rev`
[1] "56322"

$language
[1] "R"

$version.string
[1] "R version 2.13.1 (2011-07-08)"