Your first conversion fails due to unaccessible ESX:
2014-01-30T13:19:46.108-05:00 [03876 warning 'Default'] [,0] [NFC ERROR] NfcNewAuthdConnectionEx: Failed to connect to peer. Error: Host address lookup for server vmonce.os.oaklandschools.net failed: No such host is known
The next conversion fails due to some kind ot network error: temporary drop or similar... Could you try to repeat conversion again?
Because your disks are large you can try to turn off SSL (in converter-worker.xml) and
second guess - check if this could be an issue in your environment https://communities.vmware.com/message/2354597#2354597
HTH