Nearly a month late, but throwing it out there.
First and foremost, do you have Pet Affinity? From my understanding, this can have an effect on proc'ing. :-P
What values are you using for weapon proc? What value are you using for targettype on the spell? 
Let's say spell is "
PetAoE1" and ID is 500. 
PetAoE1 is the buff that adds the WeaponProc (effectid1 85). 
Let's assume "
PetAoE1 Trigger" is the actual AoE and it's ID is 501. The targettype of this needs to be 4.
The relevant DB info for 
PetAoE1:
	Code:
	effectid1 = 85
effect_base_value1 = 501
max1 = 0
effect_limit_value1 = 0
 The above will set 
PetAoE1 with WeaponProc as the effect, spell 501 (
PetAoE1 Trigger) as the proc, with default proc rate.
The relevant DB info for 
PetAoE1 Trigger:
	Code:
	effectid1 = 0
effect_base_value1 = 100
aoerange = 35
targettype = 4
 The above will set 
PetAoE1 Trigger to do 100 damage to all within 35 feet/yards/meters/cups-of-sugar.
-Hate