Btw, you're not bothering anyone by asking questions, especially nice easy ones, but it doesn't hurt to post what you found to solve your question rather than just that you solved it in case any others new enough to not see the problem run into the problem too.
For example, in this case you could've posted something like: "Nevermind, I found it. It's in mud.h listed as
#define ROOM_VNUM_SCHOOL 10300
".