malgrumm: yes all four of my granaries have a full compliment of workers and i also have 4 storage yards that also have max workers its just that the straw from the grain farms goes straight to either the brickwork's or the cattle ranches and then to the storage yards and the guys that have the carts full of meat, fish, gran AND chickpeas just sit there complaining that they can't off-load the food. all my granaries have a path all the way around each one in case i have to expand my food production to feed more people. my granaries are also set to accept all types of food....but there is one guy carrying 800 units of chickpeas and he's standing right next to an empty granary but he's still complaining.
It sounds like your delivery men don't have an operational route to an empty Granary. Straw is not a food stuff and is a raw material, so doesn't count. It also sounds like you might have set orders on the Granary not to accept food, or the game has assigned a delivery man from a distant field to deposit his goods in that granary, but can't reach it.
macAilpin: is this the map with all the ferry boats between three- four land masses on which you need to build? If so, set infrastructure to one so that the ferries are always operational. Second, keep the distance between the warehouses with straw and the cattle farms close. They are a pain.
I believe you are referring to the mission called On. It certainly sounds like that mission, but it could still be one of the many other missions. If my memory is correct, Chickpeas aren't available there, only Grain can be farmed (along with Flax). Chickpeas is a rare food type available to be grown (even if it can be imported a lot), so it narrows down the mission choices: another possibility is Sawu (Mersa Gawasis), but I doubt that from the other food types available.