Start EHP Installer Frontend (SDTGui): Logon refused

I was running the SDTGui in my laptop and it was shutdown

When I try to login again I get:

Logon refused

The service "DSUService" does not allow multiple clients to logon.

What can I do?

The EHPi Upgrade Service is running in AIX Unix.

The SDTGui on my laptop runs under windows.

Thanks for your help.

Julio Porras.