The 2.2 release of Webform corrects several bugs and adds new features to the CSV download feature. Now you can configure your download at the node/x/webform-results/download page, including a direct Excel file download.
This version is also much better about running the upgrade from Drupal 5 to Drupal 6. Previous releases required upgrading to the latest Drupal 5 version, then upgrading to 6. Any previous version of Webform should now work when upgrading from Drupal 5 to 6.