After migrating from 2.30 to 2.32 the tasks folder in the legacy .evolution data folder was not cleaned up properly.

I observed this migrating from Ubuntu 10.10(2.30.3) to 11.04 (2.32.2) as well as a straightforward upgrade from 2.30 to 2.32 within 10.10. 

In both cases I had no "Tasks" in the initial 2.30 configuration.  During the load of 2.32, the following message appears on the console,

Migrating cached data
Migrating config data
Migrating local user data
  rmdir /home/imac/.evolution/tasks
  FAILED: Directory not empty (contents follows)
          tasks

Inspecting the file structure, there is simply an empty directory:

imac@imac-VirtualBox:~/.evolution/tasks/tasks/views$

It may be worth noting that when I first upgrade, I had a number of data locations in .evolution that did not migrate cleanly.  Each of these eventually disappeared as I refreshed and corrected other configuration issues from the migration.  Here is the original load, executed with 

CAMEL_DEBUG=all evolution >& evo.log

I removed the numerous "mv" lines

Migrating cached data
  rmdir /home/imac/.evolution/cache
  FAILED: Directory not empty (contents follows)
          addressbook
          calendar
Migrating config data
  rmdir /home/imac/.evolution/addressbook/config
  rmdir /home/imac/.evolution/addressbook/views
  rmdir /home/imac/.evolution/calendar/config
  rmdir /home/imac/.evolution/calendar/views
  rmdir /home/imac/.evolution/mail/config
  rmdir /home/imac/.evolution/mail/views
  rmdir /home/imac/.evolution/memos/config
  rmdir /home/imac/.evolution/memos/views
  rmdir /home/imac/.evolution/tasks/config
  rmdir /home/imac/.evolution/tasks/views
Migrating local user data
  rmdir /home/imac/.evolution/mail/local
  rmdir /home/imac/.evolution/mail/rss
  rmdir /home/imac/.evolution/mail/vfolder
  rmdir /home/imac/.evolution/mail/imap
  rmdir /home/imac/.evolution/mail/pop
  rmdir /home/imac/.evolution/signatures
  rmdir /home/imac/.evolution/tasks
  FAILED: Directory not empty (contents follows)
          local
          tasks
  rmdir /home/imac/.evolution/memos
  FAILED: Directory not empty (contents follows)
          local
  rmdir /home/imac/.evolution/cache
  FAILED: Directory not empty (contents follows)
          addressbook
          calendar
  rmdir /home/imac/.evolution/addressbook
  FAILED: Directory not empty (contents follows)
          local
  rmdir /home/imac/.evolution/mail
  rmdir /home/imac/.evolution/calendar
  FAILED: Directory not empty (contents follows)
          local

Migrating cached data
  rmdir /home/imac/.evolution/cache
  FAILED: Directory not empty (contents follows)
          addressbook
          calendar
Migrating config data
Migrating local user data
  rmdir /home/imac/.evolution/tasks
  FAILED: Directory not empty (contents follows)
          local
          tasks
  rmdir /home/imac/.evolution/memos
  FAILED: Directory not empty (contents follows)
          local
  rmdir /home/imac/.evolution/cache
  FAILED: Directory not empty (contents follows)
          addressbook
          calendar
  rmdir /home/imac/.evolution/addressbook
  FAILED: Directory not empty (contents follows)
          local
  rmdir /home/imac/.evolution/calendar
  FAILED: Directory not empty (contents follows)
          local

My steps to get rid of the rest of these FAILED warnings (except the tasks one described here) basically were:
1) kill 2.30 processes still preset after upgrade and restart
2) for each Google calendar, select properties and re-retrieve the calendar list, which synced the calendars
https://bugs.launchpad.net/ubuntu/+source/evolution/+bug/761013
3) correct the address book issues
https://bugzilla.gnome.org/show_bug.cgi?id=648045