ExpanDrive 2.0.0 problems w/ a slightly weird filesystem configuration

I'm having problems with ExpanDrive 2.0.0 and a hybrid Linux-Windows network.

Here's the situation: I'm using ExpanDrive to reach a Linux server. The Linux server, in turn, has a few network drives (from a Windows server) mounted. I'm trying to use ExpanDrive to reach the Windows shares via the Linux machine, since the available SFTP options for Windows servers are clumsy and/or expensive for no good reason. This worked at one time using an older version of ExpanDrive, but it's not working now.

ExpanDrive is reporting a permission problem (when creating a new folder via Shift-Command-N from the Mac Finder, for example), but I think the permissions are actually set correctly. As evidence of this: a user on the Linux machine, logged in with the same credentials ExpanDrive is using, can create/delete/rename/modify files in the part of the filesystem that lives on the Windows server.

The SMB mount from the Linux machine to Windows is done using a Windows user with full administrative rights, and the permissions on the mount permit any valid Linux user access. As further evidence, it appears that the write operation from ExpanDrive is often (or maybe always) succeeding despite the error message (in the example above, trying to create a new folder from the finder will result in a permissions error, but will also create the folder anyway).

I realize this sort of problem is usually caused by administrator cluelessness, and that an error message stating a permission problem usually means just what it says. But while I won't rule out a dumb mistake on my part, I think I've checked all of the really obvious things.

I'm the administrator of all of the servers in question, and am willing to provide access for the ExpanDrive team if it's helpful in reproducing/diagnosing this issue. Thanks very much.