[Tinyos-help] graphviz version is not suitable for tinyos2.0

[牛田野]

Dear Sir\Madam:
   I am a graduate student in the University of Sci&Tec of China.
Right now I'm studying the tinyos2.0. I have installed all the files
in your website except for the last one: graphviz.
   What I have installed is version 2.8. When I execute the command 
tos-check-env, there is a warning:"the graphviz version found by tos-check-env
is not 1.10.Please update your graphviz version if you would like to use nescdoc
documentation generator "
   Would you please help me solve this problem? I cannot find graphviz version
1.10 on your web. Thank you very much!
                                              Yours Sincerely 
                                          Tianye Niu
                                          2006.11.24