problems with rpubchem package on fedora

Hi,
I tried to run rpubchem in R 2-12.0 on Fedora 13, after installing XML and RCurl'.

The sequence of commands were , just following the paper by Rajarshi Guha.

aids <- find.assay.id("lung+cancer+carcinoma")

sapply(aids, function(x) get.assay.desc(x)$assay.desc)

After quite a while the following message was returned:

Warning message:
In download.file(url, destfile = tmpdest, method = "internal", mode = "wb",  :
  RxmlNanoFTPGetConnection: failed to create socket

What is the meaning and how to fix it?

Thank you

Andreas