I really like this game, but I'm now head-first in deep "trouble".
My finest warrior became tribal queen, we completed 7 heroquests and are at peace with most of our neighbours. (Most are in the clan)

But for some reason the tribe's falling apart, claimants demanding she step down for not following our ancestor's or something like that. Even though we've spent quite some time over the years on diplomatic missions and such this keeps popping up.

Additionally, the food supply isn't improving despite several quests, splits, trades, favors and whatnot. Any idea what I'm doing wrong?

If they are saying you are angering your ancestors, it sounds like you're not upholding the promises you made during Tribe-making. Do you remember what sort of promises were made when you formed the Tribe? Failling to keep up these promises can lead to unhappiness with you as a leader, and how I lost my first tribe (and short game), as I had promised to keep the roads free of bandits, was lax in exploration and keeping the weaponthan patrols up, and started getting that message after a few events related to bandit problems as a result. If you don't, well... remember to keep that in mind next time...

As for food, have you tried clearing more wildland for farmland and pastures? or perhaps setting the sliders to plant more wheat and barley instead of rye? The clearing of wildland is the big one, and something you need to remember to do every few years as your tula grows.

Sorry for the late reply, but as far as I can remember I did uphold the tribal promises, heck I've sent plenty of things over to the Urholdi (pig fanatics), have had a Vingan on the throne for ages (as promised to another Vinga-mad clan) etc.

As for pastures and such, there's more than enough, but not enough farmers ever. I've done more Ernalda feeds etc. quests than I care to recount. I've cut back a bit on the raiding, but only because my Tula is currently bordered by those who'm I can't raid due to agreements.

Anyway, thanks for your tips, maybe the barley/rye slider will do something...
The sad thing is I suck at these games, but I love them never the less.

Making the tribe happy done in small increments with diplomacy, but the right heroquests can make them ecstatic in a year or two.

I usually run chalana arroy heals the scars for two years following the formation of a tribe (choosing the heal the rifts in the tribe benefit) and they are up to jubilent. This then shuts up the other clans and let me get on with the rest of the game in peace.

prototype00

Most of the tribal agreements are automatic, though additional gifts never hurt.

Barley/rye is almost never that important, it would only affect your own clan's harvest in any case.