Were you ever able to solve this issue. I've recently started having the same problem on my Windows 7 system (physical) when attempting to upload or download files from the datastores. I'm runnig vmWare 5.0 with vCenter 5.0 and vSphere Client 5.0 as well. (build 623373).
I also tried uninstalling and reinstalling the vSphere Client and I tried turning on verbose logging and duplicating the problem and from what I can see in the log file (not having a normal download to compare to) The call is made to start the download with the lines
[viclient:SoapTran:P:24] 2013-05-29 08:58:13.262 Invoke 82 Start FileManagement on NfcService:nfcService [vcenter server].
[operationID:9568DF6C-00000052][Caller: VpxClientCommon.DatastoreBrowserClient.FileTransferProgressBar.PerformFileTransfer]
[viclient:SrvMsg :P:24] 2013-05-29 08:58:13.262 RMI Request Vmomi.NfcService.FileManagement - 82
<ds type="ManagedObject">Datastore:datastore-10 [vcenter server]</ds>
and a few milliseconds later I see the following.
[viclient:SoapTran:P:24] 2013-05-29 08:58:13.278 Invoke 82 Finish FileManagement on NfcService:nfcService [vcenter server] -
Serial:0.003, Server:000.015
[viclient:SrvMsg :P:24] 2013-05-29 08:58:13.278 RMI Result Vmomi.NfcService.FileManagement - 82
<Result type="Vmomi.HostServiceTicket">
<Host>esx host</Host>
<Port>902</Port>
<SslThumbprint>F6:F2:89:6A:5D:B7:6E:73:FD:1B:E9:71:1C:CF:C1:1D:2A:8E:88:AA</SslThumbprint>
<Service>vpxa-nfc</Service>
<ServiceVersion>1.1</ServiceVersion>
<SessionId>52 6a 68 b5 c6 1e 0c 08-c7 7e d3 a6 f9 73 7e 95</SessionId>
</Result>
Unless there's some clue in the result block above that I am not seeing, I see no indication of an error or explanation for why the download didn't happen.
Also note we have another administrator with the same workstation as I have running the same versions fo vmware who does not have this problem so it is definitely something specific to my system. I just can't tell what. Does anyone have any more ideas?
Thanks in advance
Ray