I experienced a similar issue with VMware Converter 6.0 last week whilst trying to convert a Hyper-V 2008 R2 VM to VMware ESXi 5.5. The error message was totally misleading as it was not a network problem at all. I managed to resolve my issue by modifying the configuration of the destination virtual disks.
You can find more information here - http://timcarman.net/2015/07/20/vmware-converter-the-operation-experienced-a-network-error/