Cipher: Failed to reserve envelope space

I am trying to encrypt / decrypt a SQLite database via FireDAC in a Delphi XE7 application running on Windows 7 (64 bit).

The code looks like this:

Procedure TMain.ActionBtnClick(Sender: TObject);
Begin
If ActionBtn.Caption = 'Encrypt' Then
   Begin
   SetPassword;
   FDSQLiteSecurity.SetPassword;
   End
Else
   FDSQLiteSecurity.RemovePassword;
SetStatus;
End;

Procedure TMain.DBNamePropertiesButtonClick(Sender: TObject; AButtonIndex: Integer);
Begin
If OpenDialog.Execute Then
   Begin
   DBName.Text := OpenDialog.FileName;
   SetStatus;
   End;
End;

Procedure TMain.FormClose(Sender: TObject; Var Action: TCloseAction);
Var
   Reg: TRegistry;
Begin
Reg := TRegistry.Create;
Try
   Reg.OpenKey('\SQLiteSecurity', True);
   Reg.WriteString('Database', DBName.Text);
Finally
   Reg.CloseKey;
   Reg.Free;
End;
End;

Procedure TMain.FormShow(Sender: TObject);
Var
   Reg: TRegistry;
Begin
DBStatus.Caption := '';
Reg := TRegistry.Create;
Try
   Reg.OpenKey('\SQLiteSecurity', True);
   If Reg.ValueExists('Database') Then
      Begin
      DBName.Text := Reg.ReadString('Database');
      SetStatus;
      End;
Finally
   Reg.CloseKey;
   Reg.Free;
End;
End;

Procedure TMain.SetPassword;
Var
   s: String;
Begin
FDSQLiteSecurity.Database := DBName.Text;
BEK(s);
FDSQLiteSecurity.Password := s;
End;

Procedure TMain.SetStatus;
Begin
DBStatus.Caption := FDSQLiteSecurity.CheckEncryption;
If DBStatus.Caption = '<unencrypted>' Then
   ActionBtn.Caption := 'Encrypt'
Else
   ActionBtn.Caption := 'Decrypt';
End;

      

        
        
        
      

    

When you try to encrypt on a line that reads "FDSQLiteSecurity.SetPassword;", you receive the following error message:

[FireDAC] [Phys] [SQLite] ERROR: Cipher: Failed to reserve envelope space.

I tried to find the meaning of this error message with no success. Does anyone know what the SQLite error message is trying to tell me?