psexec Permission denied error

In the course of my DBA and software dev tasks, I make extensive use of Mark Russinovich's excellent PSTools. Today I ran across an odd error while running a remote command using psexec. Filenames have been changed, obviously, but here's the gist of it:

> psexec \\remotemachine python \\fileserver\script.py param1 param2

python: can't open file '\\fileserver\script.py': [Errno 13] Permission denied

So it was obviously opening python, which I double-checked by running with the -i option and checking the remote machine's desktop using VNC Viewer. The python shell was opening successfully, but it couldn't access the file server. Executing the script directly from the remote machine's command line worked fine.

Then I realized that this was the same issue that one gets from too (two? ;) many linked server hops using integrated authentication - it's a two-hop Kerberos problem. Google that if you don't know what I'm talking about. Fortunately, psexec offers the option of passing a username and password, and as soon as I added those options, my command executed successfully.