Thr are some things that i noticed.
(1) U have used the school tag as an "Empty Tag". The attribute listing is only to pass values and nothing can be displayed unless they are placed within the open and close tags.

(2) Place the attribute listing as separate declarations:
Like this:

<!ATTLIST school yr CDATA #REQUIRED>
<!ATTLIST school nm CDATA #REQUIRED>

I haven't worked in XML b4. So if someone else can contribute here, i can learn too. Hope this helps.

- Jemima.