Can't save Sapling presets

I’m using the sapling add-on with Blender 2.74 and when I tried to save a preset everything went screwy.

Here is the error I got:

Traceback (most recent call last):
  File "/Applications/Blender 2.74/Blender 2.74.app/Contents/Resources/2.74/scripts/addons/add_curve_sapling/__init__.py", line 100, in execute
    f = open(os.path.join(getPresetpath(), filename + '.py'), 'r')
FileNotFoundError: [Errno 2] No such file or directory: '/Applications/Blender 2.74/Blender 2.74.app/Contents/Resources/2.74/scripts/addons/add_curve_sapling/presets/Low-Poly Pine 1.py'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Applications/Blender 2.74/Blender 2.74.app/Contents/Resources/2.74/scripts/addons/add_curve_sapling/__init__.py", line 108, in execute
    f = open(os.path.join(getPresetpath(), filename + '.py'), 'w')
PermissionError: [Errno 13] Permission denied: '/Applications/Blender 2.74/Blender 2.74.app/Contents/Resources/2.74/scripts/addons/add_curve_sapling/presets/Low-Poly Pine 1.py'

location: <unknown location>:-1

Does anyone know what causes this?
Thanks

OK, I’m going to answer my own question here.
The error occurs because it can’t find the presetname.py file. And it can’t find that file because it never gets saved to begin with. And it doesn’t get saved because only the OS X user who is admin has permission to write to the directory.

To fix this I logged in as admin, went to the Applications folder, did a “Get Info” on “Blender 2.74” (the folder containing my Blender.app file), went to the Sharing & Permissions section, and clicked the “+” button to add the other user account to the permissions list. I gave this user access to Read & Write. And I clicked the gear icon at the bottom and selected “Apply to enclosed items…” so that those permissions would be applied recursively through all the subdirectories inside Blender.app.


Just posting in case someone else finds this helpful.