Courses Display Error - Launching in 3 Days :S

Hey Guys,

I just updated the date for each of the lessons on our site and received this error!

Please help as I have no idea what it means and we're set to open in 3 days on Jan 31st and it's stressing me out a little haha.

Each of the courses has added their 12 weeks of lessons, but when I'm locking the lessons sequentially thereafter, it's bringing up the error:

Warning: array_key_exists(): The first argument should be either a string or an integer in !!!ContentRemoved!!html/wp-includes/cache.php on line 725