She had migrated the legacy payroll system to a new server three hours ago. The old one, a wheezing dinosaur named NOSTROMO-1, had finally given up the ghost. The new machine— sleek, powerful, unnamed— was refusing to talk to the Oracle database.
To verify that you've downloaded the correct version of Oracle.DataAccess.dll, right-click the file, select "Properties," and then click on the "Details" tab. The file version should be 4.112.3.0. oracle.dataaccess.dll version 4.112.3.0 download
This version of ODP.NET is "unmanaged," meaning it acts as a wrapper around native C++ Oracle client libraries. If oraociei11.dll is missing from the system path, the application will crash on the first connection attempt. She had migrated the legacy payroll system to