Ah, that is much more descriptive.

I don't run a 64-bit OS, but I've heard that XP64 has some problems with running 32-bit programs. I searched around the internet and I found a couple of the files in a 64-bit version for you to try. If that fails, I have a plan B.

Step 1) Since you are running from a flash drive, create a directory called "home" in the GCCG folder. This makes GCCG save its settings on the flash drive and creates a portable installation.
Step 2) Download the 64-bit version of perl (used in the installer) from here.
Step 3) Extract perl.zip to the GCCG folder and overwrite the 32-bit files.
Step 4) Run "Install LotR.bat" again and cross your fingers!
If this doesn't work, I have another idea that
will should!
EDIT: Just spent 20 minutes typing this only to find that you figured out another way.

You should still create the
home directory if you want it to be portable, though.