I looked it up, it was in July 2009. What I remember is that Biljana could not afford to wait any longer, while Kata was struggling with injuries.
Thanks, I guess he's referring to this from Kata: "There were three hurdles for me in those 10 months - the first two were the injuries and the third was I lost my coach after Wimbledon. She had different ambitions - she picked to travel with another team on Tour. We had many good years but in this whole situation I realized who really cares for me and who always will. The ones who stuck by me are the true friends." link
The article is from August 2009, any idea which player's team she's referring to? Biljana only started working with Lucie Safarova in late 2010.
Understandable from both sides I suppose (that Biljana couldn't afford to wait and that Kata might be a little upset about it), and looks like they're alright now anyway.