请问为什么我的.vim插件文件里加了cs add cscope.out之后就出错啊

Question

我的~/.vim/plugin/cscope_map.vim的42行是
cs add cscope.out

但是vim启动的时候就会提示这个错误：
$ vim
      3 [main] gvim 5536 exception::handle: Exception: STATUS_ACCESS_VIOLATION
   1164 [main] gvim 5536 open_stackdumpfile: Dumping stack trace to gvim.exe.stackdump
      3 [main] gvim 5980 exception::handle: Exception: STATUS_ACCESS_VIOLATION
    875 [main] gvim 5980 open_stackdumpfile: Dumping stack trace to gvim.exe.stackdump
      3 [main] gvim 4364 exception::handle: Exception: STATUS_ACCESS_VIOLATION
   1079 [main] gvim 4364 open_stackdumpfile: Dumping stack trace to gvim.exe.stackdump
      4 [main] gvim 3424 exception::handle: Exception: STATUS_ACCESS_VIOLATION
   1278 [main] gvim 3424 open_stackdumpfile: Dumping stack trace to gvim.exe.stackdump
      3 [main] gvim 2340 exception::handle: Exception: STATUS_ACCESS_VIOLATION
   1040 [main] gvim 2340 open_stackdumpfile: Dumping stack trace to gvim.exe.stackdump
      2 [main] gvim 5696 exception::handle: Exception: STATUS_ACCESS_VIOLATION
    856 [main] gvim 5696 open_stackdumpfile: Dumping stack trace to gvim.exe.stackdump
      3 [main] vim 5432 fork: child -1 - died waiting for longjmp before initialization, retry 0, exit code 0x600, errno 11
Error detected while processing /home/dachuan/.vim/plugin/cscope_maps.vim:
line   42:
E622: Could not fork for cscope
Press ENTER or type command to continue

但是如果我去掉这一行，在vim正常启动之后输入:cs add cscope.out，就没有错了。请教解决办法。我的环境是cygwin+vim72

谢谢。