An announcement was posted in the Announcements Forum regarding the launch errors and eBay Preview errors. Here is a copy of the announcement:
As of 8:48am PST, we have no longer been able to launch listings to eBay through the API, nor update the status of existing items. We have notified eBay of these errors, and are working with them to resolve them. We will update this announcement frequently as we receive updates from eBay.
Please refer to the announcement for updates on this issue. Thank you for your patience.