Airport time capsule data can't be read

I have recently purchased an airport time capsule and have been backing up all of my computers to it. I wanted to check and make sure my backups were successful before deleting any material but when I click on the airport and attempt to open one of the data folders, they say "the following disk image can't be read" and the reason stated is "the image is temporarily unavailable".

How can I check and make sure my backups are successful?

Thank-you!