Replace the 'forage for berries' reaction with this for it to work:
[NAME:forage for berries]
[BUILDING:PEACE_GLEN:CUSTOM_SHIFT_F]
[REAGENT:A:1:BOX:NONE:NONE:NONE][BAG][EMPTY][PRESERVE_REAGENT]
[PRODUCT:1:1:PLANT:ROOT_HIDE:PLANT_MAT:ROOT_HIDE:STRUCTURAL][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:ROOT_HIDE:PLANT_MAT:ROOT_HIDE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:ROOT_HIDE:PLANT_MAT:ROOT_HIDE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:ROOT_HIDE:PLANT_MAT:ROOT_HIDE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:ROOT_HIDE:PLANT_MAT:ROOT_HIDE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_PRICKLE:PLANT_MAT:BERRIES_PRICKLE:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[PRODUCT:1:1:PLANT:BERRIES_STRAW_WILD:PLANT_MAT:BERRIES_STRAW_WILD:PLANT][PRODUCT_TO_CONTAINER:A]
[SKILL:HERBALISM]
The issue was a ton of typos and that you can't give someone plant structure, only the plant
I'm loving the mod so far. One thing I really like is that all the quick building material, is balanced by a bunch of other factors (like no digging). I was having so much fun building a grove wood tree that I almost didn't notice we were running out of food!
Edit:
What was that in the OP about switching between fort mode and adventure mode "at a whim"? That sounds like it shouldn't be possible.
DFHack has a change mode tool that allows such things (with bugs of course). A certain Forumite, known as Rumrusher, developed a way to "retire" a fortress using it. If you want more information look at his sig.