Not sure, but maybe worth a try. Select an ESXi host as the target (if I read the logs correctly, you selected vCenter Serer!?), and also verify that the source/Windows 2003 server is able to resolve that ESXi host's hostname as well as its FQDN, e.g. by adding a hosts entry like 10.1.2.3 esxi-host esxi-host.domain.local. The hosts file may require a blank line at the end, i.e. <CR><LF> after the entry.
André