You might need to get new Auth Tokens for your eBay accounts. If that still does not work for you, please open a ticket here and include a link to this forum thread.
That issue is being caused by the autoloader and has been addressed already. Please make sure that you are using the latest version of WP-Lister, which is 1.9.6.
The issue reported here shouldn’t stop orders from being imported. We’ve been looking for your email but we couldn’t find. Please resend it and I’ll look into your issue today.