I probably revealed the error. I'm using Chakra Linux 64bit. I've installed the game in /Games/Avadon (have a dedicated partition for games) but the start fails as reported above. Looking at the strace just before the segfault the binary tries this:
access("/games/avadon/avadon files/graphics core/g132.png", F_OK) = -1 ENOENT (No such file or directory)
(it should be ..."/Games/Avadon/avadon files/graphics core/g132.png"...)
As you can see, there is a lowercase() function somewhere in the code.
I removed the game, created a symlink games->Games and installed in /Games/avadon: now the game starts.