[R] Using R2HTML

[Gianluca Emireni]

Hello,
I'm using R2HTML library to make a HTML page output (both data frames and
graphics):

HTMLStart(outdir=paste(getwd(),"/prove html", sep = ""),filename="index",
echo = F, HTMLframe = T, withprompt = "HTML> ", CSSFile = "R2HTML.CSS",
Title = "Indici di attività")
...

barplot(tab41[,2],main="...",ylab="%",names.arg=rownames(tab41),cex.names=0.
7)
grid(nx=0,ny=NULL,lty=2)
barplot(tab41[,3],main="...",ylab="",names.arg=rownames(tab41),cex.names=0.7
)
grid(nx=0,ny=NULL,lty=2)
barplot(tab41[,4],main="...",ylab="giorni",names.arg=rownames(tab41),cex.nam
es=0.7)
grid(nx=0,ny=NULL,lty=2)

HTMLplot(Caption=paste("Indici di attività - centro
n.",cod.centro),GraphDirectory = get(".HTML.outdir", env = get("HTMLenv",
envir = .GlobalEnv)), GraphFileName = "ind-pos",Align = "center")

	But I get this error:

Error in dev.print(png, file = AbsGraphFileName, width = 400) :
	can only print from screen device
Execution halted

Can anyone help me?
Thanks