We found the solve to this problem: there are some bugged English version of the game around, even original ones like mine (
). The working English version, 100% bug free is the 2.0e English Version with the main executable (LOF file) dated 17-oct-1990. This is available only on TOSEC for now, but it will be released by SPS soon. These are the working TOSEC images:
Legend of Faerghail v2.0e (1990)(Rainbow Arts)[a](Disk 1 of 3)
Legend of Faerghail v2.0e (1990)(Rainbow Arts)[a](Disk 2 of 3)
Legend of Faerghail v2.0e (1990)(Rainbow Arts)[a](Disk 3 of 3)(Boot)
The SPS german version,
Legend of Faerghail v1.8 (1990)(reLINE)(De)[0524] works fine without the riddle bug.
More info here:
http://eab.abime.net/showthread.php?t=34864