Hi Deaner,
Welcome to VMware communities !!!.
Looks like it is not able to get the disk properties of the Linux Mahcine.
2013-04-05T09:44:49.810-07:00 [03732 error 'vmomi.soapStub[0]']
--> Required property diskId is missing from data object of type ConverterStorageInfoVolumeInfo
-->
--> while parsing serialized DataObject of type converter.info.StorageInfo.VolumeInfo
--> at line 7, column 1737
Can you check if the Operating System is supported for Converter ?, also please verify the below articles.
http://www.vmware.com/support/converter/doc/conv_sa_501_rel_notes.html#guestos
Also read the best practices guide for using VMware conveter.
kb.vmware.com/kb/1004588
http://blogs.vmware.com/kb/2010/01/best-practices-for-using-vmware-converter.html
All the best