Have you added any extensions to Chrome that may be blocked by Windows Firewall, or themselves may block file transfers?
You may more simply need to uninstall Chrome, then re-install it, as troubleshooting such a rare error message could prove timely.
To receive a Not a Number error is odd in itself, making me wonder whether the binary encoding of the transferred file becomes corrupted; but given you mention you can upload with Internet Explorer fine, does seem to suggest its uniquely a Google Chrome problem.
By the way did you think to check via eBay's own forums about this issue? Perhaps one of their technicians will be aware of some new bug. Mind you, if you are not using their Photo Uploader they may not support you.