Problem with ManTools without MSDE

Hi,
I need to install Avast!Management Tool without MSDE on my server (SQL Server 2000 SP4)
After the credential of the Server, the Setup return to me this warning:

avast! Management Tools

Couldn’t locate SQL server CESARI.
You have specified incorrect SQL server name or login.
Do you want to continue?

Sì No

But, this Server exist.

How can resolve the problem ?

Best Regards
Gaetano