Using the latest CVS, loading a Mach-O FAT file will crash HTE. The problem is that the 0xcafebabe magic is ambiguous between a Java class file and a Mach-O FAT header. A patch to fix it is attached. Tested on both a class file and a Mach-O FAT file.
Can you send me a FAT file? I don't really like the patch but I commited in anyway. There yould be a cleaner fix.
I'm not happy about the way the disambiguation works either, but it's the same logic that file(1) uses. Have a look at the cafebabe file in the file(1) magic database.
I've attached a copy of /bin/ls from a mac for verification.