ok I am installing this on a Windows box inside Virtualbox ,I was following the beginners install guide ( ARCH wiki) and when I got to the install x part I went to the virtualbox area and tried to continue from there.
I issued the pacman -S virtualbox-archlinux-additions command which worked good but when I modprobe -a vboxguest vboxsf vboxvideo
I recieved the error in my title . to try and figure out what was going on I cd to /lib/modules and checked to see what was here and only found 3.1.1-1-ARCH , extramodules-3.1ARCH and lostandfound
I am trying to figure out why the command modprobe -a vboxguest vboxsf vboxvideo is looking for 3.0-ARCH/modules.dep and how I get it to point at the proper one.
that is of course that is what it is supposed to do.
how do I fix this?

the instructions fail to tell you is to go into the Virtualbox settings and under the IDE remove the install disk once you do this and then reboot everything works .
if I would have knew this yesterday morning well, I would have been fully installed in less them 15 minutes instead of the 1.75 days it took me . lol
I guess that this could be saved as Solved now