4.2.1 spellbooks

[Tibarius]

Trying to mod the mage class spells, i get an 'error reading item'.

All i do is renaming 'First Spells' into 'Mage Spells' in all ocurrances in
class.txt. Magic books are defined in object_base.txt and realm.txt.
No more entries in object.txt (like in some older versions).

Anyone has a clue why that error occurs? It looks like some hardcoded stuff
isn't available in the /gamedata directory for modifing.