Use SCP to copy your Workstation files over to the ESX server. The path is /vmfs/volumes/YourDataStore. Next, ssh into your ESX server and run the following command:

vmkfstools -i sourcefile.vmdk /vmfs/vmfsname/destinationfile.vmdk

Once that process is complete you can point ESX at that file and start it up. Make sure you delete the source files so you aren’t wasting space on the ESX server.

via Righteous Hack » Converting VMWare Workstation images to VMWare ESXi 3.5.

This worked.  The VMware converter failed on two VMs made with Workstation but copying them over and using this command does the trick.  Problem solved! (I hope)

Converter completely failed on Windows 7 and apparently there’s a hack where the type of OS needs to be changed in Workstation settings for the VM.   My PBX in a flash vm wouldn’t boot from its hd after conversion because the converter lost its partition.  I confirmed this by booting vm into knoppix and checking the partitions.  IMHO, converter creates more work than just copying the vm manually.  I fixed my piaf vm by manually copying the .vmdk file over and using the command above.  Will do more experiments later.