Double-clicking the app doesn't work at all on Mac OSX 1.6.x.
Using the command line doesn't work either: 
sage: notebook()
 /Applications/Sage-4.7.2-OSX-64bit-10.6.app/Contents/Resources/sage/sage: line 39: /Users/admin/.sage/local/bin/sage-sage: No such file or directory
 ValueError                                Traceback (most recent call last)
 /Users/admin/.sage/<ipython console=""> in <module>()
 /Applications/Sage-4.7.2-OSX-64bit-10.6.app/Contents/Resources/sage/devel/sagenb/sagenb/notebook/notebook_object.pyc in __call__(self, args, *kwds)
    215     """
    216     def __call__(self, args, *kwds):
--> 217         return self.notebook(args, *kwds)
    218 
    219     notebook = run_notebook.notebook_twisted
 /Applications/Sage-4.7.2-OSX-64bit-10.6.app/Contents/Resources/sage/devel/sagenb/sagenb/notebook/run_notebook.pyc in notebook_twisted(self, directory, port, interface, address, port_tries, secure, reset, accounts, require_login, server_pool, ulimit, timeout, open_viewer, sagetex_path, start_path, fork, quiet, subnets)
    200         print '*' * 70
    201 
--> 202     nb = notebook.load_notebook(directory)
    203 
    204     directory = nb._dir
 /Applications/Sage-4.7.2-OSX-64bit-10.6.app/Contents/Resources/sage/devel/sagenb/sagenb/notebook/notebook.pyc in load_notebook(dir, interface, port, secure)
   1807     # mainly to avoid circular references, etc.  This also means
   1808     # only one notebook can actually be used at any point.
-> 1809     import sagenb.notebook.twist
   1810     sagenb.notebook.twist.notebook = nb
   1811 
 /Applications/Sage-4.7.2-OSX-64bit-10.6.app/Contents/Resources/sage/devel/sagenb/sagenb/notebook/twist.py in <module>()
     64 java_path            = os.path.join(DATA)
     65 
---> 66 jsmath_image_fonts = is_package_installed("jsmath-image-fonts")
     67 
     68 # the list of users waiting to register
 /Applications/Sage-4.7.2-OSX-64bit-10.6.app/Contents/Resources/sage/local/lib/python2.6/site-packages/sage/misc/package.pyc in is_package_installed(package)
    168         True
    169     """
--> 170     return any(p.startswith(package) for p in install_package()) 
    171 
    172 def standard_packages():
 /Applications/Sage-4.7.2-OSX-64bit-10.6.app/Contents/Resources/sage/local/lib/python2.6/site-packages/sage/misc/package.pyc in install_package(package, force)
    125         if __installed_packages is None:
    126             X = os.popen('sage -f').read().split('\n')
--> 127             i = X.index('Currently installed packages:')
    128             X = [Y for Y in X[i+1:] if Y != '']
    129             X.sort()
 ValueError: list.index(x): x not in list