<p>How know what is means ?
You have chosen a course at the University of Oxford and a course at the University of Cambridge.This is only possible if you already have a suitable degree or will have been awarded a suitable degree by 30 September 2012.</p>
<p>You cannot apply for both Oxford and Cambridge at undergraduate level, you have to choose just one of them. However if you are applying for a Graduate programme then you can apply to both universities. The message is just checking you’re applying for Grad not UG courses.</p>
<p>I agree with pemphredo that you can’t apply to both Ox and Cam for undergraduate in the same year, unless you are an organ scholar. However, I think you can also apply to both if you are applying for a second undergraduate degree (which is what I think the error message refers to, as UCAS isn’t used for grad school applications).</p>