Hi,
I am trying to upgrade Moodle 2.6 to 2.7 and than to 3.2. Or 2.6 to 3.0.8 to 3.2. But for some reason I can't. This is the error:

Coding error detected, it must be fixed by a programmer: The data source class does not exist.

Debug info:
Error code: codingerror
Stack trace:
line 498 of /cache/classes/definition.php: coding_exception thrown
line 515 of /cache/classes/helper.php: call to cache_definition::load()
line 480 of /cache/classes/helper.php: call to cache_helper::purge_store()
line 323 of /admin/index.php: call to cache_helper::purge_all()