I was able to get the newest version of Adobe Flash Player to work in Firefox Portable by doing the following:
- Copy from "c:\windows\system32\macromed\flash" the "flashplayer.xpt" and "npswf32.dll" files to the WinPE "\firefox\data\plugins" folder.
- Copy from "c:\windows\system32" the "ddraw.dll", "dsound.dll", "glu32.dll", "mscms.dll" and "opengl32.dll" files to the WinPE "\windows\system32" folder.
Hope this is of help to someone.