Ошибкой завершилось следующее действие:
Demand
Ошибкой завершилось первое разрешение следующего типа:
lcpi.data.oledb.OleDbPermission
Ошибкой завершилось первым следующее разрешение:
<IPermission class="lcpi.data.oledb.OleDbPermission, lcpi.data.oledb.net4_6, Version=1.0.1.2490, Culture=neutral, PublicKeyToken=ff716095e8002e7e"
version="1"
AllowBlankPassword="False">
<add KeyRestrictions=""
KeyRestrictionBehavior="AllowOnly"/>
</IPermission>

Было предъявлено следующее требование:
<IPermission class="lcpi.data.oledb.OleDbPermission, lcpi.data.oledb.net4_6, Version=1.0.1.2490, Culture=neutral, PublicKeyToken=ff716095e8002e7e"
version="1"
AllowBlankPassword="False">
<add KeyRestrictions=""
KeyRestrictionBehavior="AllowOnly"/>
</IPermission>

Для сбойной сборки был предоставлен следующий набор:
<PermissionSet class="System.Security.PermissionSet"
version="1">
<IPermission class="System.Security.Permissions.SecurityPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
Flags="SkipVerification, Execution, SerializationFormatter"/>
</PermissionSet>

Ошибкой завершилась следующая сборка или AppDomain:
lcpi.data.oledb.ntest.net4_6, Version=1.0.0.1326, Culture=neutral, PublicKeyToken=ff716095e8002e7e
Причиной этого явился следующий метод:
Void Exec__OleDbConnection_GetNativeSession(lcpi.data.oledb.OleDbConnection)
Ошибкой завершилась сборка со следующим параметром Zone:
MyComputer
Ошибкой завершилась сборка со следующим параметром URL:
file:///D:/Users/Dima/Work/.NET/data.oledb.net/ntest/bin/vs2015_net46.0_Release/lcpi.data.oledb.ntest.net4_6.DLL

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <!--
   The GUI only runs under .NET 2.0 or higher. The
   useLegacyV2RuntimeActivationPolicy setting only
   applies under .NET 4.0 and permits use of mixed 
   mode assemblies, which would otherwise not load 
   correctly.
  -->
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <!-- Comment out the next line to force use of .NET 4.0 -->
    <supportedRuntime version="v4.0.30319" />
  </startup>
  
  <runtime>
    <useLegacyJit enabled="1" />

    <!-- Ensure that test exceptions don't crash NUnit -->
    <legacyUnhandledExceptionPolicy enabled="1" />

    <!-- Run partial trust V2 assemblies in full trust under .NET 4.0 -->
    <loadFromRemoteSources enabled="true" />
    
    <!-- Look for addins in the addins directory for now -->
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <probing privatePath="lib;addins" />
    </assemblyBinding>

  </runtime>

</configuration>

using System;
using System.Security;
using System.Security.Permissions;

using xdb=lcpi.data.oledb;
//using xdb=System.Data.OleDb;

namespace ConsoleApp
{
 public class Program
 {
  public class tagHelper : MarshalByRefObject
  {
   public void Exec(xdb.OleDbConnection cn)
   {
    //var x=cn.BeginTransaction();
    var x=cn.GetNativeSession();

    //Console.WriteLine("Exec.point #2");

    x.Dispose();
   }//Exec
  };//class tagHelper

  public static int Main()
  {
   try
   {
    var cn=new xdb.OleDbConnection("provider=lcpi.ibprovider.3;location=d:\\database\\employee.fdb");

    cn.Open();

    var testDomain=helper__create_domain();

    // Create helper object in sandbox AppDomain so that code can be executed in that AppDomain.
    var helperType
     =typeof(tagHelper);
 
    var Helper
     =(tagHelper)testDomain.CreateInstanceAndUnwrap(helperType.Assembly.FullName,
                                                    helperType.FullName);
   
    helper__exec(()=> {Helper.Exec(cn);});
   }
   catch (Exception exc)
   {
    Console.WriteLine("ERROR: {0} - {1}",exc.Source,exc.Message);
   }//catch

   return 0;
  }//Main

  //----------------------------------------------------------------------
  private static AppDomain helper__create_domain()
  {
   var permissions
    =new PermissionSet(PermissionState.None);
 
   var spflags = 0
    | SecurityPermissionFlag.SkipVerification //required for .NET 3.5
    | SecurityPermissionFlag.Execution
    | SecurityPermissionFlag.SerializationFormatter //required for EnlistTransaction
    ;
 
   permissions.AddPermission(new SecurityPermission(spflags));
 
  var appDomainSetup
   =new AppDomainSetup();

  appDomainSetup.ApplicationBase
   =AppDomain.CurrentDomain.SetupInformation.ApplicationBase;

  //lcpi.data.oledb.net4_6.dll
  var a1_name=typeof(xdb.OleDbConnection).Assembly.GetName();

  //lcpi.lib.net4_6.dll               HELPER ASSEMBLY
  var a2_name=typeof(lcpi.lib.com.ClsCtxCode).Assembly.GetName();

  var a3_name=typeof(System.Runtime.InteropServices.SafeHandle).Assembly.GetName();

  //-----
  var a1_sname=new System.Security.Policy.StrongName
                    (new System.Security.Permissions.StrongNamePublicKeyBlob
                          (a1_name.GetPublicKey()),
                           a1_name.Name,
                           a1_name.Version);

  var a2_sname=new System.Security.Policy.StrongName
                    (new System.Security.Permissions.StrongNamePublicKeyBlob
                          (a2_name.GetPublicKey()),
                           a2_name.Name,
                           a2_name.Version);

  var a3_sname=new System.Security.Policy.StrongName
                    (new System.Security.Permissions.StrongNamePublicKeyBlob
                          (a3_name.GetPublicKey()),
                           a3_name.Name,
                           a3_name.Version);

  //----------------------------------------
  return AppDomain.CreateDomain("TestDomain",
                                AppDomain.CurrentDomain.Evidence,
                                appDomainSetup,
                                permissions,
                                a1_sname,
                                a2_sname);
  }//helper__create_domain
 
  //----------------------------------------------------------------------
  private static void helper__exec(Action a)
  {
   try
   {
    Console.WriteLine("helper__exec.point #1");

    a();
   }
   catch (System.Security.SecurityException ex)
   {
    Console.WriteLine("EXEC_ERROR1: {0}",ex.FirstPermissionThatFailed);
    Console.WriteLine("EXEC_ERROR2: {0}",ex.Message);
   }
  }//helper__exec
 };//class Program
}//namespace Console

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <runtime>
      <useLegacyJit enabled="1" />
    </runtime>

    <startup> 
        
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0" /></startup>
<system.data>
    <DbProviderFactories>
      <remove invariant="lcpi.data.oledb" />
      <add name="LCPI OleDb Data Provider" invariant="lcpi.data.oledb" description="LCPI .NET Data Provider for OLE DB" type="lcpi.data.oledb.OleDbFactory, lcpi.data.oledb.net4, Version=1.0.1.2490, Culture=neutral, PublicKeyToken=ff716095e8002e7e" />
    </DbProviderFactories>
  </system.data></configuration>