Update error occured. Please help ~

Greetings.

So I've played LOTRO before. And the game runs smoothly and without any problem. But then I had to reformat my pc. And after that, I reinstalled it again. And now I can't even get past the launcher. It keeps telling me 'update error occured. failed to load patchclient'. I don't understand why this problem is here now. I have no problems whatsoever before. Please help. I'm playing through Steam by the way, if that helps.

Thanks in advance.