Lone Wolf Development Forums - Action points incrementer

Hello.
I'm new here so I apologise if I post in wrong place and wrong way.

I am trying to implement Action point into my system.
Right now I've managed to set it up in similar way to power points (except it is calculated differently).
But I want to go one step further and make it faster to acces and modify by making an similar incrementer that ws used for Initiatibe in tactic form.
I copied the code from Initiative but I stuck at point when I want to access action points field.
I've got such a massage:

Code:

Hero Lab was forced to stop compilation after the following errors were detected:



Portal 'totalacts' - Reference to incompatible field type/style/behavior based on portal type

The Field which I specify is copy of health field used elsewhere in incrementer
(dmgDamage)and lies within Actor component. Here is code for it:

Code:

<field

      id="acActNow"

      name="Current Actions"

      type="derived">

      <calculate phase="Traits" priority="5100" name="Calc acHPNow">

        <after name="Calc acHPMax"/><![CDATA[

        ~@value = field[acHPMax].value - hero.usagepool[DmgNet].value

                @value = 5

        ]]></calculate>

      </field>

So what I am missing / doing wrong?
Is it some limitation to access derived fields by incrementer?
I should mention that I am not a programmer I merely get some low level script experience.