32 bit application not running on 64 bit OS

 We have a 32 bit application which we are trying to run on Windows Server 2003 64 bit machine. The service is not starting up with an error as

"COM Error: -2146824582, Source: ADODB.Connection, Description: Provider cannot be found. It may not be properly installed., error message: Unknown error 0x800A0E7A"

Below is the ConnectionString used:

std::tstringstream ssConnectionStream;

ssConnectionStream     << _T("Provider=OraOLEDB.Oracle;")

                                    << _T("User ID=") << this->GetUID() << _T(";")

                                    << _T("Password=") << this->GetPWD() << _T(";")

                                    << _T("Data Source=") << this->GetDbSource() << _T(";");

We are having 64 bit Oracle Database server installed on 64 bit machine.

Please help on above if anybody has solution for the above.