Failure to find class MigrateD2DWizard after install on Sqlite/PostgreSQL

Ditto

I simply installed the above modules, and simply clicking on the Import From Drupal button gives me the fatal error.

Same problem here.

I had the same problem, but it simply went away, when I switched the database (of the new D7 installation) from SQLite to MySQL. May be you should try this out.
HTH, Dietmar.

Can't reproduce this, works for me. I'm running Drupal 7.26 with MySQL 5.5 and PHP 5.5 on Linux.
The following migrate* modules are enabled

$ drush pml --status=Enabled | grep migrate
Development UI for Drupal-to-Drupal migration (migrate_d2d_ui) Module 7.x-2.1-beta1
Migration Drupal-to-Drupal migration (migrate_d2d) Module 7.x-2.1-beta1
Migration Migrate (migrate) Module 7.x-2.6-rc1
Migration Migrate UI (migrate_ui) Module 7.x-2.6-rc1

I would start by checking that the modules listed above are enabled, and then see if and with what path the "MigrateD2DWizard" is registered in your Drupal database.

SELECT * FROM registry WHERE name = 'MigrateD2DWizard';

If the class is missing from the registry, or if the file path is not correct then I would recommend rebuilding the registry.

https://drupal.org/project/registry_rebuild

Hope this helps.

I've found this problem using PostgreSQL database.

I was able to reproduce this on a fresh Drupal install with sqlite (using drush qd). Doing either a "drush cc all" or "drush rr" fixes it, suggesting that somehow the initial module install is not resulting in the class being properly registered. But - I've verified the registry and registry_file tables are correct initially, and are not changed by the drush commands. So, somehow there's a failure to cache the registry entry for the MigrateD2DWizard class on initial install.

I can't imagine what migrate_d2d might be doing to foment this behavior - it feels like a core bug. I'm reluctant to move this to the core issue queue without digging deeper to understand why this is happening, though.

The bug is present, Drupal 7 and SQLite.

Related issue: #2286547: Lowercase Migrate wizard class name in hook_menu breaks Migrate UI with SQLite & PostgreSQL

Just struck this on postgres 9.1 too. I can confirm that the suggestion to drush cc all fixes it.

Once working it can be forced back into the same broken state by clicking the Register Statically Defined Classes button on the configuration screen.

vagrant@truenet7:/var/www/sites/all/modules$ drush pml --status=Enabled | grep migrate
 Development       Drupal-to-Drupal migration UI (migrate_d2d_ui)       Module  7.x-2.1-beta1+28-dev 
 Migration         Drupal-to-Drupal migration (migrate_d2d)             Module  7.x-2.1-beta1+28-dev 
 Migration         Migrate (migrate)                                    Module  7.x-2.6-rc1+65-dev   
 Migration         Migrate UI (migrate_ui)                              Module  7.x-2.6-rc1+65-dev

The fix nevergone mentions works for postgres too. I'm going to close this and mark as a duplicate as #2286547 has a working patch.