Mishomi,
Interesting...
So when you install other games, are the installation boxes also in gibberish or is it actually Japanese?
aphelion_orion's link should be helpful in case there are any mixups in between with setting the language:
HERE
Also when you downloaded Alex, there was only the file 'boot.exe'? It should have came as two .iso files (that is, if you were downloading from my post XD)
AH! I just realized something. I don't know if it's relevant to this game in particular but I've noticed that some games (as in their .iso, .cue, or .bin files) are not compatible with certain mounters (ie Heartner Hearts with PowerISO). So I'm wondering
maybe that could also be the case.
DAEMON Tools (this is the light version) is pretty much universal as I haven't come across a game that can't be compatible with the program. Maybe you might want to take a stab at that as well.
No worries! I know the frustration of wanting to play a game badly but can't because of issues with installation. I just hope that I'm actually helping and not confusing you even more ^^;