Time Machine - Error 22 Randomly Appears

My Time Machine backup has been throwing up a message for the last hour or so, saying that it cannot create a new sparsebundle, with 'Error 22' also included in the message. While it's tempting to say this is an OS upgrade problem, Time Machine had been backing up fine for about 24 hours with Lion before this problem occurred.

I've found a few solutions which say to rename the computer, the wireless network and the disk that the backup is on. I've changed both the disk and the computer names, but I'm hesitant to change the network name as all the other tech in my house would need to be reconfigured, and I don't think that's the problem as it was backing up fine up to an hour ago. Also, I can still see the previous backups and restore from them fine, so there doesn't appear to be a corrupt file or anything.

What's exactly the problem, why has it appeared so randomly, and how can I fix it?

Thanks in advance for your help!