[R] XML - can create but can't save

[Alberto Monteiro]

What's wrong with this?

library(XML)
tt <- xmlHashTree()
head <- addNode(xmlNode("head"), character(), tt)
test <- addNode(xmlNode("test", attrs=c(pi="4")), head, tt)
tt # ok
saveXML(tt, file="test.xml") # error

The error (in Portuguese) is:
Erro em saveXML(tt, file = "test.xml") : nenhum método aplicável 
para "saveXML"

which could translate to
Error in saveXML(tt, file = "test.xml") : no method applicable to "saveXML"

Alberto Monteiro