You can try adding the --copy-server-side flag with the stardog-admin db create .... command. I realize that you're running the client and server on the same machine but since you're running it as two separate users Stardog may be having trouble accessing the file. Running as admin doesn't necessarily mean it can access the file. I'm not a Windows person but between windows ACL's and access controls from it possibly being on a separate SMB share mean it's not guaranteed to be able to access it even though it's admin.
Didn't notice that the file was located in the Admin user directory. That lowers the probability that what I suggested would work but you can give it a try. Are you running both the client and server as admin?
This looks like an error I was seeing with Oracle's JRE 8u331. I noticed that Oracle had recently released JRE 8u333, so I uninstalled 8u331 and installed the newer version, and Stardog started working on Windows.