I have a CGI-application that I have developed in Delphi. The webserver is IIS4 on Windows NT. The application uses ADO to access an 9iR2 Oracle database on a Unix platform, using Oracle Objects for OLE, and has been working great.
This week we have upgraded our webserver. It now runs W2K SP4 and IIS5. Now the application can no longer connect to Oracle, and we receive the following message:

Provider cannot be found. It may not be properly installed

I use the following connection string:
Provider=OraOLEDB.Oracle.1;Password=xxxx;User ID=yyyy;Data Source=doc1

I have also some GUI applications, also built with Delphi. They are installed on the same new machine where IIS is running and access the same Oracle database, also using ADO and Oracle Objects for OLE. In fact, they use the exact same connection string. They all work without a glitch..! It is only the IIS application that does not work.

I did a search at metalink, which learned me this was a Microsoft issue, as I had suspected. At Microsoft I found KB article 255084 which I followed step by step. I used different connection strings (using MSDAORA, ODBC, etc.), all without result. I have granted full rights to both IIS users to the Oracle home directory, and I've set SQL.AUTHENTICATION(_SERVICES) to none in SQLNET.ORA. Nothing helped...

Any other clues? I am new to this forum, so please tell me if this is not the right place to post my questions.

Thanks in advance for your help!