[R-sig-Debian] package XML does not load in R 2.15.1

[John Kane]

I am getting what appears to be an Unbuntu level error in trying to install the 
XML package.

Both commands:
install.packages("XML:)
install.packages("XML", dependencies = TRUE)
 give an error .

The full installation script is below but the problem to my very inexperenced eye seems to be here:

checking for pkg-config... /usr/bin/pkg-config
checking for xml2-config... no
Cannot find xml2-config
ERROR: configuration failed for package ‘XML’

I seem to have libxml1 version 2.7.8defg.1ubuntu installed if this is relevent.

Any suggestions would be gratefully received.  

 Ubuntu 12.04
sessionInfo()
R version 2.15.1 (2012-06-22)
Platform: i686-pc-linux-gnu (32-bit)

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

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

loaded via a namespace (and not attached):
[1] tcltk_2.15.1 tools_2.15.1




Full installation script.
================================================================
==================================================
downloaded 901 Kb

* installing *source* package ‘XML’ ...
** package ‘XML’ successfully unpacked and MD5 sums checked
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
No ability to remove finalizers on externalptr objects in this verison of R
checking for sed... /bin/sed
checking for pkg-config... /usr/bin/pkg-config
checking for xml2-config... no
Cannot find xml2-config
ERROR: configuration failed for package ‘XML’
* removing ‘/home/john/R/i686-pc-linux-gnu-library/2.15/XML’

The downloaded source packages are in
	‘/tmp/RtmpC85FTD/downloaded_packages’
Warning message:
In install.packages("XML") :
  installation of package ‘XML’ had non-zero exit status
===========================================================
John Kane
Kingston ON Canada

____________________________________________________________
GET FREE SMILEYS FOR YOUR IM & EMAIL - Learn more at http://www.inbox.com/smileys
Works with AIM®, MSN® Messenger, Yahoo!® Messenger, ICQ®, Google Talk™ and most webmails