If you're using rAthena SVN go to
src/map/config/Renewal.h
/**
* Renewal Cast Time
* @values: 1 (enabled) or 0 (disabled)
* 1 : Cast Time is decreased by DEX*2+INT, 20% of the cast time is not reduced by stats,
* - for example, on a skill whose cast time is 10s, only 8s may be reduced. other 2s are
* - part of a "fixed cast time" that is only reduced by special items and skills (such as
* - Arch Bishop's Sacrament skill).
* 0 : the old cast time method, influenced by dex, items and skills.
**/
#define RECASTING 1
Set the value to 0.
And your lua files, make sure you get the lua files before your client date. If you get the lua files more later than your client, things like that will mess your hotkeys, etc up.
Eurydice's post in castrate_dex_scale: 150 Thanks to [Eurydice] was marked as the answer