Should I be able to run disk utility on my Time Machine Backups?
TimeMachine is rock solid. I have used it extensively and exclusively since it came out at on many different machines and have never lost any data. Like any backup system, it is only as reliable as the person using it. You need to have multiple disks rotated at regular intervals. Time Capsule is just one Time Machine disk, so don't confuse the two. You need additional Time Machine backups on other disks. Unfortunately all disks fail eventually. If it says that the last back was a certain date then that is what you have.