Those errors are usually on the Windows side. Behind the scenes, all the LEM is doing is a mount -t cifs //yourserver/yourshare /tmp/smb -o user=youruser,domain=yourdomain,password=yourpassword.
Please note that mount.cifs notoriously has issues with multi-layer share paths. If your share is \\yourserver\yourshare\a\folder\way\down\the\line\lem\backups, mount.cifs will probably fail. It wants to connect to \\yourserver\yourshare. If you really want to send stuff to the .\lem\backups folder in that example, you should share it directly so you can use the path \\yourserver\backups or (at worst) \\yourserver\lem\backups.