I just installed this interesting plugin, and after installing it on other website that I own, I tried with other website I created, and I get this error:
Fatal error: Call to undefined function backwpup_send_no_cache_header()
It's weird, because I'm using exactly the same WP release (3.1), on the same server.
It happens to me always, no matter what kind of backup I set (only file backup, only DB backup, etc.)
Any idea about what can be the problem?