Thanks for the suggestion. I do have a VPN set up, but no mapped drives, so I looked into that a little but it did not seem to be involved.
One other observation: The "load" command works from the console. Is the "open" button in the GUI doing something different than "load"? I guess it is, because even if a successful "open" results in a "load" command in the end, "open" has the additional process of browsing to the desired file, and since the file browser never comes up, it's not getting to the load command.