sdemon command line: cannot connect to database

Dear all,
I have installed on a Client with SO VISTA:
- ArcSDE 10.1 Command lines +SP1.
- ArcGIS Desktop 10.1 + sp1 +qi.
- oracle instant client: instantclient-basiclite-win32-11.2.0.1.0

On a Linux server I have an enterprice geodatabase (direct connection architecture) on linux/oracle11gr2

Now, when I execute sdemon by cmd:

sdemon -o status -i sde:oracle:<ipserver>/<sidname> -s<ipserver> -usde

the following error appear:

Cannot connect to database because the database client software failed to load.
Be sure the database client software is installed and configured correctly., Un
able to get instance configuration

Why?

If I connection ArcMAP to Oracle with the some parameter the connection work fine.

Regards