Ah, I see then. Sorry for the patcher before--didn't know about it--and thanks for the answer now.
Originally Posted by RedHawke
The crystal is not compatible with short or double sabers, only use it in the normal lightsaber hilts. You will get crashes or "null nade's" if you attempt to do so. This same general rule applies to many lightsaber mods.
Hmm... I've just tried to put the white crystal on normal red lightsaber, and it causes the same error. But when I replace a Segan Wyndh saber crystal with a red crystal, it works...
Ah yes, and another bug (maybe?). The mod works fine on my save file, the "Rune Covered Pillar" appears after I talked to Lashowe. But on my another save file, it won't appear even I have killed them. I've tried changing map, but it's still won't appear.