无法在 Ubuntu 11.04中安装 R 软件包

我是 Linux 和 R 的新手。

我在 Ubuntu 11.04中安装了 R 2.12。今天我尝试安装一个新软件包，所以我运行了以下命令:

install.packages('XML')

但是安装失败了，提供了以下信息:

* installing *source* package ‘XML’ ...
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/spirit/R/i686-pc-linux-gnu-library/2.12/XML’


The downloaded packages are in
‘/tmp/RtmpoZYxnv/downloaded_packages’
Warning message:
In install.packages("XML") :
installation of package 'XML' had non-zero exit status

我也试过:

sudo install.packages('XML')

但它提供了相同的错误信息。

有人能给我点建议吗？