R 3.0.2上的rpart库包安装错误

Question

发出命令：

install.packages("rpart")

错误：

Installing package into ‘/home/priyanka/R/x86_64-unknown-linux-gnu-library/3.0’
(as ‘lib’ is unspecified)
Warning: unable to access index for repository http://cran.cnr.Berkeley.edu/src/contrib
Warning message:
package ‘rpart’ is not available (for R version 3.0.2) 

我尝试过cloud-0和Berkley CRAN网站。 请指导我如何解决此问题。