Error in csv_enrol when using block "Users/Personen"

[Former user]

I get following error if i have click "Teilnehmer" in my course and the block csv_enrol is included in the course. (see Screenshot)

(used version:$plugin->version = 2013050101; )

Datensatz kann nicht in der Datenbanktabelle course gefunden werden Debug info: SELECT id,category FROM {course} WHERE id = ? [array ( 0 => 0, )]

Error code: invalidrecord Stack trace:

line 1451 of /lib/dml/moodle_database.php: dml_missing_record_exception thrown
line 1427 of /lib/dml/moodle_database.php: call to moodle_database->get_record_select()
line 6884 of /lib/accesslib.php: call to moodle_database->get_record()
line 37 of /blocks/csv_enrol/block_csv_enrol.php: call to context_course::instance()
line 288 of /blocks/moodleblock.class.php: call to block_csv_enrol->get_content()
line 230 of /blocks/moodleblock.class.php: call to block_base->formatted_contents()
line 999 of /lib/blocklib.php: call to block_base->get_content_for_output()
line 1051 of /lib/blocklib.php: call to block_manager->create_block_contents()
line 335 of /lib/blocklib.php: call to block_manager->ensure_content_created()
line 19 of /theme/grips_responsive/layout/default.php: call to block_manager->region_has_content()
line 915 of /lib/outputrenderers.php: call to include()
line 845 of /lib/outputrenderers.php: call to core_renderer->render_page_layout()
line ? of unknownfile: call to core_renderer->header()
line 1673 of /lib/setuplib.php: call to call_user_func_array()
line 164 of /user/index.php: call to bootstrap_renderer->__call()
line 164 of /user/index.php: call to bootstrap_renderer->header()

Maybe anybody can help?