Note: This error may be fixed in the newest Hotmail Connector.
We're seeing error 4102 reported more frequently since the release of the new Outlook Hotmail Connector. One astute user tracked it down to using only the Hotmail Connector data store in his profile (or setting it as default) – Outlook created the RSS feed folders and tries to upload them to the Hotmail/Live account and the Live servers don't want them.
The fix: add a pst to the profile and set it as default or disable RSS feeds using a registry key.
Complete instructions are here: Remove RSS Folder
Published May 19, 2011. Last updated on September 12, 2013.