尝试在 ubuntu 12.04 上安装 ns-2.33 时出现以下错误。我怎么解决这个问题
m -f embedded-tcl.cc
./tcl2c++ et_tcl ../lib/tcl8.4/init.tcl ../lib/tcl8.4/history.tcl ../lib/tcl8.4/word.tcl ../lib/tcl8.4/http1.0/http.tcl > embedded-tcl.cc
/bin/sh: 1: ./tcl2c++: Permission denied
make: *** [embedded-tcl.cc] Error 126
tclcl-1.19 make failed! Exiting ...
See http://www.isi.edu/nsnam/ns/ns-problems.html for problems