Redirecting output isn't goint to help if the program wants input. You probably want to make sure you've redirected anything in stdin/stdout/stderr that you don't want the child to inherit from the parent. Of course, nohup will do that for you for stdout/stderr. Try one of the following depending on how much input the program needs...

#  You need EOF on input...
system("nohup program </dev/null >/dev/null 2>&1 &");
#  You need 1 line of empty input...
system("/bin/echo | nohup program >/dev/null 2>&1 &");
#  You need infinite lines of empty input
system("yes '' | nohup program >/dev/null 2>&1 &");
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... all of which are kludgey and assume you don't care about error handling here (e.g. no nohup output; does program really start up ok?).

bluto