This script will work inside a trigger zone for plrfreeze. I think I know what you did wrong but here is the script
;Artificial Intelligence Script
;Header
desc = player freeze for 10 seconds inside zone.
;Triggers
:state=0,plrwithinzone=1:plrfreeze=10000,state=1
:state=1,plrwithinzone=0:state=0
;End of Script
EDIT:
As soon as the player hits the edge of the trigger zone he will freeze for 10 seconds and then be released. When the player walks out of the trigger zone, it will be reset to work again.
This should have been in the X10 forum. This works in X9. I don't have X10.