@vorsta I experienced the same problems when I upgraded. I read that switching to Manual mode for Minify fixes things but I always had it on Manual mode (Enter URLs in manually) so this wasn't a solution for me.
I just downgraded the plugin and everything (mostly) went back to normal. Downgrading took me a while though and caused a series of problems, including 500 errors, missing URL settings for minify, etc... To bypass the issues, you should either disable Minify completely or attempt to downgrade.
I'm going to hold off on upgrading until I notice a newer version available and can confirm that these errors are fixed. I don't want to waste tons of time reverting an upgrade again.
It should be fixed in the next version according to the Twitter account: https://twitter.com/#!/w3edge/status/71126092286660608