Hi Lisa,
Is it still there, even after reloading the page? Is it a fresh WordPress install – and if so, perhaps something went wrong with the install?
The meaning of the message is that some broken code from another entity is preventing UpdraftPlus from running. If it’s not from another plugin or theme, then take a look at your ‘Plugins’ page to see if there are any “MU-Plugins” or “Drop-ins” active. Failing that, perhaps the WordPress install just didn’t completely properly and something’s missing from WordPress.
David