ORA- 02041 : client database did not begin a transaction ORA- 06512 : at "WH.PKG_WH", line  469  ORA- 06512 : at line  1 

namespace DBTIER {
	public class workstations {
		public OracleDataReader getOwners() {
			OracleConnection conn = new OracleConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
			OracleCommand cmd = conn.CreateCommand();
			cmd.CommandType = CommandType.StoredProcedure;
			cmd.CommandText = "WH.PKG_WH.get_owners";
			cmd.Parameters.Add(new OracleParameter("t_cr", OracleType.Cursor)).Direction = ParameterDirection.Output;
			conn.Open();
			OracleDataReader Rd = cmd.ExecuteReader(CommandBehavior.CloseConnection);
			return Rd;
	}
}

You are running into Oracle Client  8 . 1  client bug  914652 . This problem was
exposed when we added Distributed transaction support to the Oracle Client
v1. 1 . There is a QFE available from our side that allows you to completely
disable distributed transactions by using a connection string keyword
(Enlist=false is not enough), please contact pss directly for the fix.

A better option would be to switch to a newer version of the Oracle Client,
this issue is fixed in v9.x
Hope this helps

sConnection = "Provider=OraOLEDB.Oracle;Password=" & sDatabasePwd & ";User ID=" & sDatabaseSchema & ";Data Source=" & sDatabaseInstance & ";DistribTX=0;"

System.ArgumentException: Keyword not supported: 'distribtx'.

public OracleDataReader getOwners() {
	OracleConnection conn = new OracleConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
	OracleCommand cmd = conn.CreateCommand();
	conn.Open();
				
	cmd.Transaction = conn.BeginTransaction(IsolationLevel.ReadCommitted);
	cmd.CommandText = "SET TRANSACTION READ ONLY";
	OracleDataReader Rd = cmd.ExecuteReader();
	Rd.Close() ;
								
	cmd.CommandType = CommandType.StoredProcedure;
	cmd.CommandText = "WH.PKG_WH.get_owners";
	cmd.Parameters.Add(new OracleParameter("t_cr", OracleType.Cursor)).Direction = ParameterDirection.Output;
				
	Rd = cmd.ExecuteReader(CommandBehavior.CloseConnection);
	cmd.Transaction.Commit();
	return Rd;
}