drupal:
I fought my way through the upgrade from Drupal 5.19 to 5.20, to 6.14, yesterday:
1. Re-install all previously-installed modules and then uninstall them via Drupal interface.
2. Upgrade from Drupal 5.19 to 5.20 -- no errors or warnings; site seemed okay.
3. Upgrade from Drupal 5.20 to 6.14, study errors and warnings, restore back to Drupal 5.20, verify, and then use mysql client to drop problematic tables:
cache_block cache_form menu_router menu_links menu_custom upload actions_old_contrib actions_aid search_node_links
4. Upgrade to Drupal 6.14 -- no errors or warnings; site seems okay:
I'm going to wait a while before I attempt steps 3 and 4 on my other Drupal 5.x site.
HTH,
David