各位大佬，小弟想做PSD,在用findit psmatch2 安装时，出现了下面的问题，该怎么破
connection timed out -- see help r(2) for troubleshooting
http://fmwww.bc.edu/RePEc/bocode/p/ either
  1)  is not a valid URL, or
  2)  could not be contacted, or
  3)  is not a Stata download site (has no stata.toc file).