I have the same problem. The Change Settings, Manage Space, Backup now and Turn off Schedule buttons are not working. Nothing happens when I click on them.
I discovered this after I created a weekly backup job to a network location. The job was running fine for a few weeks.
Then one day I was fooling around in the backup and restore center and for some reason pressed the Turn off Schedule button. And then I couldn't enable the backup job again (I pressed the button but nothing happened).
So, until I find a permanent solution I use work-arounds :
1. enable the job by starting the task scheduler and enable the job from there. Edit start time here also if you want.
2. to execute Change Settings : sdclt.exe /configure
3. to execute Backup Now : sdclt.exe /kickoffjob
4. to execute Space Management : /spacemgmt
At least there is a way around it for those keen to backup their goodies.
Note: I upgraded my Vista64 to Windows7-64. Maybe something went wrong, causing this. I have another Windows7 computer (clean install). There I don't have this problem.