Application cannot open connection to Oracle database - missing DLL OraOps9.dll

Question

My .NET application tries to connect to an Oracle database, but the connection fails to open because it cannot find "OraOps9.dll".

xxx.CreatedbConnection() failed to open connection.
System.DllNotFoundException: Unable to load DLL (OraOps9.dll).
   at Oracle.DataAccess.Client.OpsTrace.GetRegTraceInfo(UInt32& TrcLevel)
   at Oracle.DataAccess.Client.OracleConnection..ctor(String connectionString)
   at Utilities.Database.OracleDBConnection.Open()
   at xxx.CreatedbConnection(String userName, String password)

The Oracle client is installed but that DLL is not present in my Oracle Home bin\ folder (C:\oracle\ora92\bin\). Where can I get this DLL?