<ERROR> instead of custom / base config waila tooltip

[AlexGuignard]

Hi i'm having an issue where even with default configs when i look at a furnace it showns no burn time but instead
I didnt see this issue anywhere in this github
modlist :
modlist.pdf
other question would this work for a custom furnace script ?

<!--Date: 2015/2/8-->
<!--Version: 1.7.10-->
<oo>
    <init>
        function tick2second(n){return parseInt(n/20)}
    </init>
    <tileentity id="Furnace">
        <line displayname="Burn Time">
            return "Cook time : " + tick2second(nbt['BurnTime']) + " | Cooked items : " + nbt['Items'][3]["Count"]<!--Author: EpixZhang-->
        </line>
    </tileentity>
    <entity id="Sheep">
        <line displayname="Until next love">
            tick2second(nbt['InLove'])
        </line>
    </entity>
    <tooltip id="minecraft:skull">
        <line displayname="OwnerName">
            return nbt['SkullOwner']
        </line>
    </tooltip>
</oo>