very nice!
I changed the english.lang a little bit, it's attached. (as .txt)
also, the configure and play buttons don't seem to work for me...see attached picture. Looks like it's failing because of spaces in file names.
great app, and great idea
p.s. by opening the demo.cmd generated by your app you can clearly see why it's failing with spaces....needs quotes!

(see attached)
p.s.s- i think it would be better if you change the operating directory to the pcsx2 root folder, and then do something like:
rundll32 plugins\gsdx.dll,GSReplay snap\<.gs filename>
that's just how i would do it
so.....in my case:
cd "C:\Documents and Settings\Shawn\Desktop\Pcsx2" & rundll32 plugins\gsdx.dll,GSReplay snap\gsdx_20080102153734.gs
which is: cd "<path to pcsx2 dir in quotes>" & rundll32 plugins\gsdx.dll,GSReplay snap\<.gs filename>