I'm trying to install Mathematica 9.0.1 on my work laptop, running Maverick. (I know, I know... )

The result:

Enter the installation directory, or press ENTER to select /usr/local/Wolfram/Mathematica/9.0:

Now installing...


Type the directory path in which the Wolfram Mathematica script(s) will be created, or press ENTER to select

Installation failed. See /usr/local/Wolfram/Mathematica/9.0/InstallErrors.
The InstallErrors file has one line:
xdg-desktop-menu: No writable system menu directory found.
I found a whole pile of mostly confusing Google results. What I've gathered is that this error apparently has *something* to do with the installer trying to install a .desktop file. But I'm not sure just what the fix is. Can anyone offer a suggestion?