Ok, if your having problems use this patched batch file
Click Here, Put GUI in C: Drive, put magic, menu and flevel in GUI folder, put unlgp and lgp in GUI folder, put the new batch file in the GUI folder and run it (doesn't have to be run as an admin), copy all the lgp files back and put texture file in ff7 directory, put seffect1.tex in the battle folder and replace the old one.
The new Batch File has a pause command, so look through the steps it has done, if anything says failed then report back.