iCloud for Windows did not install properly. To repair it, you need to go to Apps and features, select iCloud Outlook from the app list and click Modify. When prompted, click on Repair.

Fix iCloud error An error occurred during authentication while connecting iCloud with Windows 11/10, in order to sync data.

At least, to my I've-not-used-an-iPad-really-before mind this is the only other route I've figured for this rather inclusive file management system. Have you managed to make iCloud work on Windows XP?