The solution is quite simple: When using the thumbnail preview mode of windows explorer for grafic files Windows XP generates an internal database for the thumbs with the extension *db. Normally it's hidden and encrypted because it's handled as a system file. If you choose 'show all extensions' you may click on it and delete it before you make a copy. It's more or less useless.(and definitely no original part of your runtime) The error message normally occurs when you try to save the folder on a CD or another storage.