I've tried a few injectors lately and I noticed that AVA is tricky to inject into.
First of all, when I'm playing and I look in the process list, there is no actual process in the list, and it always fails to inject, using PerX or Valkyrie. The one time Valkyrie did infact inject successfully, I press Delete in-game and nothing happens. (MPGH Public Hack)

I am running Windows XP.
Does anyone know if I'm forgetting something?