the probelm of ns & pgm

[yyshen <yyshen@mail.nj.cims.edu.cn>]

hello
    i met a problem when i embeded pgm into ns.
    when i installed ns ,i didnot meet the following problem .
    but when i embed pgm into ns , i found the problem when i  run a
simple program:
                  Invalid command name " Simulator" while executing
"Simulator create _o1"
                            invoked from within  "catch" $className
create $0 $args "msg"
 who can tell me how to do?
thanks !!