Random robots.txt issue!

Hi,
I set up a blog just over a week ago, everything was going great until yesterday. Before new content was being indexed by google within a few minutes then it just stopped.
I looked at google webmaster tools and it looks like i had a robots.txt blocking access to everything, i made a new robots.txt and uploaded it so hopefully it should sort itself out.

The thing is i don’t know how this could have happened; i’ve not touched the privacy settings and can’t see any other settings that would cause this. Is it possible that a plugin could have caused this? I’m trying to work it out so it doesn’t happen again but really i have no ideas!

Jo