我在加载fPortfolio程序包时出现了一下错误，求大神解答？？？

程序包‘robustbase’打开成功，MD5和检查也通过
程序包‘Rglpk’打开成功，MD5和检查也通过
程序包‘slam’打开成功，MD5和检查也通过
Error in read.dcf(file.path(pkgname, "DESCRIPTION"), c("Package", "Type")) :
  无法打开链结
此外: Warning messages:
1: In download.file(url, destfile, method, mode = "wb", ...) :
  downloaded length 3239936 != reported length 3815038
2: In download.file(url, destfile, method, mode = "wb", ...) :
  downloaded length 110592 != reported length 130700
3: In download.file(url, destfile, method, mode = "wb", ...) :
  downloaded length 258048 != reported length 1067072
4: In unzip(zipname, exdir = dest) : 从zip文件中抽取1时出了错
5: In read.dcf(file.path(pkgname, "DESCRIPTION"), c("Package", "Type")) :
  无法打开压缩文件'Rsymphony/DESCRIPTION'，可能是因为'No such file or directory'