Make sure you don't use that enrolment plugin (disable it if you are using 1.6.x, or choose another one if using 15.x) and remove the directory where the enrolment plugin resides and then make.
Then delete all the settings for that enrolment plugin from mdl_config and mdl_config_plugins.
Saludos. Iñaki.
Enrolment
Custom enrollment plugins
This discussion has been locked so you can no longer reply to it.