Danmakufu: Custom Item Data issue

//Item_Script.txt, copy-pasted from official Danmakufu ph3 documentation on item scripts, comments removed.
@Initialize
{
    SetDefaultBonusItemEnable(false);

    let dir = GetCurrentScriptDirectory();
    LoadItemData(dir ~ "Item_Data.txt")
}

@MainLoop {
    yield;
}

@Event
{
    alternative(GetEventType())
    case(EV_GET_ITEM)
    {
        let itemType = GetEventArgument(0);
        let objItem = GetEventArgument(1);
    }
    case(EV_DELETE_SHOT_TO_ITEM)
    {
        let objShot = GetEventArgument(0);
        let objPos = GetEventArgument(1);

        TUserItem(objPos[0], objPos[1]);
    }
}

task TUserItem(let itemX, let itemY)
{
    let obj = CreateItemU1(1, itemX, itemY, 10000);
    ObjItem_SetDefinedMovePatternA1(obj, ITEM_MOVE_TOPLAYER);
}
//End of script


//Item_Data.txt
#UserItemData

item_image = GetCurrentScriptDirectory() ~ "Point Sheet.png"
//Error: "item_image is not defined." on startup.

ItemData { //Power Item
	id=0
	value=0
    AnimationData {
        animation_data=(10,3,3,16,16)
        animation_data=(10,19,3,32,16)
    }
	out=(35,3,48,16)
}

ItemData { //Point Item
	id=1
	value=1
    AnimationData {
        animation_data=(10,3,19,16,32)
        animation_data=(10,19,19,32,32)
    }
	out=(35,19,48,32)
}

ItemData { //1UP
	id=2
	value=2
    AnimationData {
        animation_data=(10,51,3,84,36)
        animation_data=(10,85,3,118,36)
    }
}

ItemData { //Bomb
	id=3
	value=3
    AnimationData {
        animation_data=(10,51,35,84,68)
        animation_data=(10,85,35,118,68)
    }
}
//End of script


//System.txt (only the initialize section)
@Initialize
{
    StartItemScript(GetCurrentScriptDirectory() ~ "Item_Script.txt");
	//a bunch of system tasks after...
}