title: Strange error on Excel Workbook input
body: <p>For the current code:</p>
  
  <pre><code> String currentPath = Directory.GetCurrentDirectory();
  
          OpenFileDialog op = new OpenFileDialog();
          op.InitialDirectory = currentPath;
          if (op.ShowDialog() == DialogResult.OK)
              currentPath = op.FileName;
          else
          {
              toolStripStatusLabel1.Text = "Failed to Load Workbook";
              toolStripStatusLabel1.Visible = true;
          }
  
          Workbook wb = new Workbook(excel.Workbooks.Open(currentPath));
  </code></pre>
  
  <p>I recieve the error:</p>
  
  <p>System.Runtime.InteropServices.COMException was unhandled
    Message=Retrieving the COM class factory for component with CLSID {00020819-0000-0000-C000-000000000046} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).
    Source=mscorlib
    ErrorCode=-2147221164</p>
  
  <p>All I want is a predefined workbook to add worksheets to</p>