In the title, there doesnt have to be a ".txt"
I'm not sure if the uppercase/lowercase effects anything, but, just to be safe, keep it all lowercase.

When you open your game.txt, it should look like this. (Atleast, mine does)

ms0:/seplugin/BakonICE.prx
ms0:/seplugin/nitePR.prx
ms0:/seplugin/InfMic.prx
ms0:seplugin/AntiBoot.prx

After each new prx, {example= after ms0:/seplugin/BakonICE.prx , you just press enter to get to the next line.At this next line, you right the next prx (ms0:/seplugin/nitePR.prx).

You dont need an empty line between each prx.