Greetings.
That may be related to your vmware role permissions level (according to a much older vsphere article)
See https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009284
Can you try using winSCP, and see if you can copy off/to that way?
You may need to check some of your vsphere host logs (vmkernel, hostd, etc)
Is this a stand alone vsphere host, or connected to vcenter?
If that is just an error generate between the vsphere client and the windows OS, then maybe try running the vsphere client GUI with 'admin' privileges. Just a guest on that one, as I haven't seen that error before.
Thanks,
Kirk...