Go to Settings -> Course administration -> backup. I click Next on each screen leaving the default. I turned DEBUG on. Instead of Backup, I get this output:
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DDL sql execution error

More information about this error [link to http://docs.moodle.org/en/error/moodle/ddlexecuteerror]
Debug info: Access denied for user 'moodleuser'@'localhost' to database 'moodle'
CREATE TEMPORARY TABLE felicia_mdl_backup_ids_temp (
id BIGINT(10) unsigned NOT NULL auto_increment,
backupid VARCHAR(32) NOT NULL DEFAULT 'ffdf214796a9c7fb7d79b0f169105849',
itemname VARCHAR(160) NOT NULL DEFAULT '',
itemid BIGINT(10) unsigned NOT NULL,
newitemid BIGINT(10) unsigned NOT NULL DEFAULT 0,
parentitemid BIGINT(10) unsigned,
info MEDIUMTEXT,
CONSTRAINT PRIMARY KEY (id)
)
Stack trace:

• line 397 of /lib/dml/moodle_database.php: ddl_change_structure_exception thrown
• line 620 of /lib/dml/mysqli_native_moodle_database.php: call to moodle_database->query_end()
• line 88 of /lib/ddl/database_manager.php: call to mysqli_native_moodle_database->change_database_structure()
• line 75 of /lib/ddl/database_manager.php: call to database_manager->execute_sql()
• line 499 of /lib/ddl/database_manager.php: call to database_manager->execute_sql_arr()
• line 141 of /backup/util/dbops/backup_controller_dbops.class.php: call to database_manager->create_temp_table()
• line 88 of /backup/util/dbops/backup_controller_dbops.class.php: call to backup_controller_dbops::create_temptable_from_real_table()
• line 39 of /backup/moodle2/backup_stepslib.php: call to backup_controller_dbops::create_backup_ids_temp_table()
• line 34 of /backup/util/plan/backup_execution_step.class.php: call to create_and_clean_temp_stuff->define_execution()
• line 153 of /backup/util/plan/base_task.class.php: call to backup_execution_step->execute()
• line 148 of /backup/util/plan/base_plan.class.php: call to base_task->execute()
• line 105 of /backup/util/plan/backup_plan.class.php: call to base_plan->execute()
• line 293 of /backup/controller/backup_controller.class.php: call to backup_plan->execute()
• line 111 of /backup/util/ui/backup_ui.class.php: call to backup_controller->execute_plan()
• line 87 of /backup/backup.php: call to backup_ui->execute()
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