esxcli: Update/patch produces “Could not download from depot” error

In ESXi 5.1 you can patch using the following command:  
esxcli software vib install -d /path/to/patch.zip
  If you’re getting the following result (using ESXi510-20121001.zip as an example):  
 [MetadataDownloadError] Could not download from depot at zip:/var/log/vmware/ESXi510-201210001.zip?index.xml, skipping ((‘zip:/var/log/vmware/ESXi510-201210001.zip?index.xml’, ”, “Error extracting index.xml from /var/log/vmware/ESXi510-201210001.zip: [Errno 2] No such file or directory: ‘/var/log/vmware/ESXi510-201210001.zip'”)) url = zip:/var/log/vmware/ESXi510-201210001.zip?index.xml Please refer to the log file for more details.
  This results from not putting in the absolute path to the .zip – e.g. using:  
esxcli software vib install -d ESXi510-20121001.zip  
rather than:  
esxcli software vib install -d /vmfs/volumes/datastore/ESXi510-20121001.zip
  Putting in the full path to the .zip file should resolve that error.