Yes, I was somewhat perplexed by this as well, although I didn't receive the same error message you did. I received no message. I thought that the settings were restored, but nothing was restored. This was upgrading from 1.11 to 1.21. Something must have gone wrong when saving the configuration file to my drive using IE7. I keep more than one file on hand (just in case), and I noticed that the one I saved just before flashing the new firmware was only about half the file size, compared to a previous one. Something must have happened during the save process. At any rate, I was able to load a previously saved file, which worked. Thank God there wasn't much difference to the configuration files in the previous saved set-up.
D-Link needs to look into this.