expandrive 1.8.3 manager shows connected but OS drive is not there

Hello,
our system is winXP-SP4.
every day we connect using net use I: \\ExpanDrive\MySFTPConnection copy some files an disconnect with net use I: /d
This works fine but every 2 or 3 days we could not make the connection with net use
net use shows no drive I: and when we try to connect we got "command successfull" but no drive I:
the manager shows that drive I: is connected, the explorer not.
when we disconnect in the manager we can connect with net use but without getting a drive I: in the command windows, but the explorer shows the drive I:
is there a function to connect/disconnect without net use and calling the drive manager from a script?