Have you checked if there was a trailing space or any other character that you might have accidentally copied and pasted into the paypal address field?
You should follow the steps explained at http://www.wplab.com/plugins/wp-lister/faq/#Debugging to send an example log record to support - then I'll be able to see exactly what was send to eBay and should be able to identify the cause.
Alternatively you can use the contact form on wplab.com to contact me directly - you might not want to post private details like your email address on this forum and I might have to ask for login details to your site with should never be posted in any forum...
kind regards,
Matt