Build 1533 is what you're running and this is what is contained in the Liveupdate, so running Liveupdate won't help!
Not that it's going to help you but for others, after running the Liveupdate on the server, you do not need to indivdually update each client, any task, including a config refresh, when executed, will upgrade the client which the task is executing against.
As to the source of the problem, can't really help you I'm afraid.
Is this happening to all your clients?
Are they connected to the server?
Cheers