stepatty on "[Plugin: BackWPup Free - WordPress Backup Plugin] Mini plugin to fix "unknown cipher" error"

I'm technically illiterate. I don't have a clue how to install the mini Plugin Daniel offered. Is there a simpler way to fix the "unknown cipher" error since I updated to 3.1.2? Can I restore 3.1.1? How do I do that? Thanks.

https://wordpress.org/plugins/backwpup/