I have just installed the latest beta (minimals) and updated my .bash_profile (as advised) so that it now reads:
. /Applications/ConTeXtMinimals/tex/setuptex /Applications/ConTeXtMinimals/tex/texmf-osx-64/bin

When I try to compile any file, I get:

FatalError      : Your format does not match the base files!

FormatVersion   : 2009.11.26 16:28 MKII
FilesVersion    : 2009.12.01 00:14

How do I fix this? (texexec --make --all did not do the trick.)

Alan