Since startx is a script to "start X"
You might wanna take a look at it. However, FYI, I had very little problems using Gentoo to configure X, so maybe one of your USE flags is stopping a needed package from getting installed. Post em up.
Another idea, what is "stratx"? Did you type it wrong? Make sure you have a wm installed (KDE, Gnome, Fluxbox, openbox...) and a corresponding entry in your HOME directory within the xinitrc. That sentence isn't very clear:
Make sure you have a file in your USER'S home directory (you should be doing this with a user as it's very rarely necessary to use root in X) (which is characterized as ~ in most tutorials) called .xinitrc and in that file you have a line that says:
So if you are using fluxbox, and it's installed to /opt/fluxbox/fluxbox then:
If your $PATH is the problem, edit /etc/profile and make sure you are editing your USER path's and not the ROOT's path.