I wanted to offer a big tip for fellow Mac OS X users who may be having difficulty getting their cron job to work for SNAP Pro.
As mentioned above, in my case, I purchased and used the app called LaunchControl. However, I kept getting an exit error of 78 with the app.
Then I discovered why, what was wrong, and how to fix it.
The problem is that by default, WordPress’s “wp-cron.php” file does NOT have a shebang line — or interpreter line — at the very top of it. You need to add it yourself. This is the line which begins with “#!”. After typing “#!” — without the quote marks — you need to add the path where your PHP binary is located.
As soon as I did that, my cron job started working, and I am happily posting to my social networks again via SNAP Pro.
I hope this bit of information helps other Mac OS X users out there.