I'm running into this error each time I try to manually archive one of my apps (xxx.xml corresponding to the app) since I had to re-install SDC for it to update to 2.48.485 Build 160.

I saved a copy of the Backup folder before uninstalling SDC, deleting the SDCentral folder and re-installing SDC; then copied the Backup folder contents back to the new Backup folder.
Any ideas out there?