Problem accessing MS SQL7 database from a web server application

Hello,
I have this problem trying to access a MS SQL 7 database from a web server
application (an ISAPI dll): the web server application tries to connect to
the database using a TDatabase component in the TWebDatamodule.OnCreate.
- If the ISAPI dll was never called and the first call to it comes from a
browser located to a pc (say pc2) other from the pc on which the ISAPI dll
is developed (say pc1), I have this message on pc1:
"Project inetinfo.exe raised exception class EDBEngineError with message
"Unknown user name or password. [Microsoft][ODBC_SQL Server Driver][SQL
Server]Login failed for user '\'.
Alias PROVA_MAX'"
- If the ISAPI dll was never called and the first call to it comes from a
browser located on pc2 (that of ISAPI dll developement), connection with
database is estabilished and all works fine. After this, any subsequent call
from a browser on pc1 works fine, too.

Does anyone experienced something similar?

Thank you in advance to anyone can help to solve this problem.
Massimo