ns-allinone-2.29"成功"后的问题

在FC4工作站版下安装ns-allinone-2.29成功后，运行#ns simple.tcl  
ns: finish: couldn't execute "nam": such file or directory
 
我看了一下，确实没有nam,上ns网站上的install problem页面找了半天，
终于看见了这个
 
problem: Ok, but I still can't run simple.tcl under the ~ns/tcl/ex directory, it gives an error saying: 
couldnt execute nam: 
no such file or directory while executing "exec nam out.nam &".
(Also, when I try typing the comamnd "ns simple.tcl", and I get the error "ns: command not found".) 
Solution: Well, you need to add nam' directory to the environment variable PATH or specify its location in the tcl script. (PATH is part of Unix, so if you're not sure how it works, please consult a local Unix expert or search the web on "unix PATH".) 
 
这个没怎么看懂，设了PATH问题仍然存在。继续寻找
 
ns-allinone-2.28
Problem: When installing ns-allinone-2.28 using gcc3.4, nam fails to build.
Solution:Try replacing the "NULL" in line 73 of file agent.h in nam-1.11 with "0". Bug reported and fix supplied by Qihe Wang.
 
我的版本是2.29，但是我还是试了一把，结果nam的问题解决了，我在nam-1目录下运行
./configure && make && make install,默认是装在/usr/local目录下，其实make install 命令只做了一件事，就是把nam可执行文件拷贝到/usr/local/bin下，我大胆的把它移到了ns-allinone-2.29/bin下，再次 运行simple.tcl，nam的问题不存在了，但是又出现了新的问题，cannot open display 之类的，我不知道怎么解决，设DISPLAY参数也不好使。暂时还没有解决方案。