.NET console app with Firebird Client crashes on program end

Question

This is a small project for a friend where the goal is to read data from a given firebird database file and put it into MS Office 2010 Templates...so both Firebird as a database backend and .NET 4.x project type office something is the given stack.

I wrote a small (console) test app to get in touch with the firebird embedded database client, and already have the first issue I don't get rid of. My Code is as follows:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using FirebirdSql.Data.FirebirdClient;

namespace TestFirebirdConnection
{
    class Program
    {
        static void Main(string[] args)
        {
            // Set the ServerType to 1 for connect to the embedded server
            string connectionString =
            "User=sysdba;" +
            "Password=******;" +
            "Database=C:\\...\\...\\...\\PDATA.FDB;" +
            "ServerType=1;" +
            "Charset=NONE;";

            try
            {
                FbConnection dbConnection = new FbConnection(connectionString);

                dbConnection.Open();

                string SQLCommandText = "select * from Patients";

                FbCommand dbCommand = new FbCommand(SQLCommandText, dbConnection);

                FbDataReader dr = dbCommand.ExecuteReader();

                while (dr.Read())  
                {
                    Console.WriteLine(dr["TITLE"] + " " + dr["SURNAME"] + " " + dr["NAME"]);

                }

                dr.Close();
                dbConnection.Close();

            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}

All works fine, the code puts out all names of a patients database on the shell. I already used the debugger to check, if the datareader and the dbConnection is closed() properly, which is the case.

After the very last line I get a nasty Windows Error Message (that kind of memory access violation) every time, where I can't find out why this is happening.

UPDATE: It seems, that it has to do with fbintl.dll

UPDATE 2: This does not happen, if I connect to a firebird server (which is unfortunately not a good solution for my light weight office template project)

Anybody knows why this is happening?

I am using:

• Firebird ADO.NET Provider 4.6 (from NuGet)
• Firebird Embedded database 2.5.3 x64

I actually am not sure with which version of firebird the database file was created