I reinstalled the game this morning, and what I'm thinking is happening is that the copy I have is an installed copy that needs to be configured, not an ISO; Boxer is setting it up as D: during the install process, but it actually needs to be on C:
So, the crash bug... I can't reproduce it with a new install. I did, however, save the gamebox; would you like me to send that to you?
Let me see if I've got this right - you've reimported it from the original files, and the new gamebox is working properly? But the gamebox you had before didn't import correctly, because Boxer had failed to detect that it was pre-installed and put the files on drive D?
Heh. Yeah, fair enough; that wasn't totally clear.
The first import (the crashing one):
Initial import failed because the install.exe apparently expected to be run from C: and could not find some of its files. I poked at it for a while, did some messing around (that I can't reproduce now) and the result is a game box that crashes Boxer when it starts up. It ran all of one time, and never since. No part of the game box was changed between first run and subsequent crashes.
The second import (the working one):
Initial import failed in the same way. However, I solved it differently, by simply moving all of the files from D: to C: and re-running install.exe. This game works.
Interesting. You shouldn't need to do any of that: Boxer's import process should do the right thing if you either a) tell Boxer to "Skip Installer" to start with, or b) run the installer, get complained at (because the installer isn't where it thinks it should be), then tell Boxer to "Finish Importing" anyway.
In the latter case, Boxer will detect that the installer didn't put anything on drive C, and assume that the original folder was a fully-installed game after all. In both cases, Boxer will then put the already-installed game folder on drive C where it belongs.
If neither of those steps did the right thing though, then there's a bug with Boxer's import process that I need to get to the bottom of. Where did you download the game from?
OK, I've tried the copy from emuparadise, and in both of the import cases I outlined above, Boxer does the right thing and imports the game as expected. The result was a working gamebox both times.
If you copied any files to drive C yourself while trying to figure out why the installer didn't work, then this would confuse Boxer's import process: it would have decided the game's installer actually worked, and then wrapped up the original source folder as a CD-ROM for drive D. (That behaviour is intended to handle folder copies of CD-ROMs, which are common.)
The short advice in these situations is: "trust in Boxer". If an installer doesn't work because the game was already installed, then it's usually safe to let Boxer finish up the import anyway. If the resulting gamebox doesn't work, then reimport the game again and choose "Skip Installer" next time.
(I'm marking this bug as "invalid" even though I hate that label, because Boxer is behaving as intended. This is not meant to imply that what you did was stupid, just that Boxer probably needs better documentation for edge-cases like this.)