Okay, this is embarrassing but I just checked again and it's working now. But it really wasn't a few minutes ago!
Lately when I go to view backups using the Time Machine interface it lists all my backups going back to April 22, 2009, but anything older than late August 2010 is blacked out and can't be clicked.
When I look in my Time Capsule disk on the finder, all the older backups are there and I can view and copy all the files.
Also, in system preferences, Time Machine preferences lists my oldest backup as April 22, 2009 and there is plenty of disk space available on the Time Capsule.
Why is this happening and what can I do to fix it?
MacBook Pro 2.4 GHz Intel Core 2 Duo