Picture explains a thousand words.
http://i.imgur.com/HW0humN.png
The decklist of the priest is standard (white colored). Tried the other standard decks and same issue.
When using a wild deck, it produces the above error and it also says "deckname can only be used in wild mode" (I ticked wild in options and I even manually ticked wild format in game). I also restarted the bot.
I went back to 5.7.6 that I had on my other PC and everything works fine again. New update definately broke something.