Windows Phone thinks i have a child account

My windows phone (and 'Zune' programme) says that I have a child account and need parental account to sign in and accept the term of use, but i don't have a child account and on my hotmail account it isn't a child account. My date of birth is correct and shows that I am over 18. How can i fix it so that i can accept the terms of use on my phone (or in the 'Zune marketplace') .. as i cannot download anything until this is resolved.