问如何修复System.IO.__Error.WinIOError(Int32 errorCode，String maybeFullPath)

EN

public void Scan(string path)
{
    string[] libs = { "CHIP", "SOT", "SMC", "SOP", "SOJ", "QFP", "PLCC", "PLCC", "SINGLE", "SIP", "DIP", "CON", "ZIG", "BRG", "PAD", "FID" };
    try
    {
        foreach (string lib in libs) 
        {
            foreach (var filePath in Directory.EnumerateFiles(path, lib +".lib"))
            {
                //This is for debugging important in order to differ between used and unused libs
                //Here i should create a new instance of a file class that way i can find the lib's back easyly
                createBackup(filePath, txtBackup.Text);
            }
        }

        foreach (var dir in Directory.EnumerateDirectories(path)) 
        {
            Scan(dir);
        }
    }
    catch (UnauthorizedAccessException) 
    {
        Console.WriteLine("Error: " + path);
    }
}

public void createBackup(string filePath, string backUpLocation)
{
    string fileToBackUp = filePath;
    string fileName;
    int lastBackSlash = filePath.LastIndexOf("\\") + 1;
    string caption;
    string message;

    fileName = fileToBackUp.Substring(lastBackSlash, fileToBackUp.Length - lastBackSlash);

    if (System.IO.File.Exists(backUpLocation + "\\" + fileName) && chk_overWriteAllBackups.IsChecked == false)
    {
        caption = "File already present!";
        message = "Would you like to override the previous back-up that is present in this folder?";

        MessageBoxButtons buttons = MessageBoxButtons.YesNo;
        DialogResult result;
        result = System.Windows.Forms.MessageBox.Show(message, caption, buttons);

        if (result == System.Windows.Forms.DialogResult.Yes)
        {
            //Backup created in the selected folder and old backup is overwriten
            //Add the name of the file to the array of backed up items
            System.IO.File.Copy(filePath, backUpLocation + "\\" + fileName, true);
            readFiles();
        }
        else
        {
            caption = "Are you sure?";
            message = "No back-up will be created are you sure?";
            result = System.Windows.Forms.MessageBox.Show(message, caption, buttons);

            if (result == System.Windows.Forms.DialogResult.Yes)
            {
                //Continue without backups
                readFiles();
            }
            else
            {
                caption = "Select diffrent back-up location?";
                message = "Would you like to select a new back-up location?";
                result = System.Windows.Forms.MessageBox.Show(message, caption, buttons);

                if (result == System.Windows.Forms.DialogResult.Yes)
                {
                    //Return the user so a new back-up location can be selected
                    return;
                }
                else
                {
                    //Continue without backups
                    readFiles();
                }
            }
        }
    }
    else
    {
        try
        {
  Error->          System.IO.File.Copy(filePath, backUpLocation + "\\" + fileName, true);
        }
        catch (IOException e)
        {
            caption = "Error";
            message = e.ToString();
            System.Windows.Forms.MessageBox.Show(message, caption);
        }

    }
    readFiles();
}