I think alpaca means descr_campaign_db.xml.

I think you are looking for this part:
Code:
   <revolt>
      <end_turn_modifier float="2"/>
      <excommunicated_modifier float="15"/>
      <new_leader_modifier float="10"/>
      <max_effective_loyalty float="7.0"/>
      <rebel_region_modifier float="2.0"/>
      <shadow_region_modifier float="2.0"/>
      <rebel_border_modifier float="1.1"/>
      <shadow_border_modifier float="1.1"/>
      <num_units_modifier float="1.05"/>
      <captain_modifier float="0.4"/>
      <min_revolt_chance float="0.0"/>
      <max_revolt_chance float="80.0"/>
      <ai_revolt_modifier float="0.25"/>
      <revolt_additional_armies bool="false"/>
      <revolt_crusading_armies bool="false"/>
   </revolt>
Just lower the max revolt chance floater.


RM3


ps. Don't take my word on it, unless you have a backup.