OMFG, you're hoping to get in to oxford and you're asking that question. Durham have not the faintest idea of whether you will/will not get into oxford. To the very best of my knowledge, unis do not give a monkeys about each other, and therefore do not talk to each other. Durham may simply assume that you are a strong Oxford candidate, and may reject you (even this idea is far fetched), or more likely, for some reason or another, they just didnt want you.
Uni's do not gamble on applicants getting in at other places, if they like you, they will make you and offer and hope you accept, if they dont, they wont.
It means nothing a rejection from durham, apart from their loss.