Mac OS X 10.0 (the version released on March 24) is substantially different
from the Mac OS X Public Beta. REALbasic 3.0 works fine on the Public Beta
but not on version 10.0. If you are using Mac OS X 10.0, you need to be
using REALbasic 3.1, currently in beta. REAL Software offers open betas,
that is anyone who wants to can download a REALbasic beta and use it.
(http://www.realbasic.com/realbasic/prerelease/)