helllo,
for ertheia class sub class should not be possible to add, simply when you reach lvl 85 on main class, you complete windos of fate quest, and u get dual class.
this is how should work, retail source
"The following is the information about how to get a sub/dual class for Ertheia. o The Ertheia race cannot create a sub-class.
o
The dual class will be available once players reach Level 85, complete the 3rd Liberation and the Winds of Fate: Encroaching Shadows quest, and talk to Raina.
o The Ertheia race's dual class is created at the Level 85 awakened class status. Only one slot is set aside for dual class.
o The dual class can be any class except for the Ertheia race class (Eviscerator/Sayha’s Seer is NOT possible), Tyrr Maestro, and Iss Dominator.
o Ertheia classes cannot learn sub-class skills since they cannot create a sub-class.
Two basic stats, LUC and CHA, have been added."
source
www.lineage2.com , or here the 75 pages pdf of patch
http://lineage2media.com/Complete%20...0Strangers.htm