Time Capsule Trouble Connecting

I have my time capsule set up with time machine in Leopard on my Macbook and it is working perfectly, backing up properly and letting me connect to the shared drive. However, occasionally when I open my computer, the time machine icon in the menu bar says the backup was interrupted, and my computer is unable to connect to my time capsule. Air port utility still sees it, and the drive still shows up in my shared drives, but it cannot connect. Restarting fixes this. Any ideas?