Backup error opening file for 2.3.3

I have been trying to back up courses on a Moodle 2.3.3  and I get the following debug info when I try to any kind of backup:

Error code: error_opening_file
$a contents: /home/learning/moodle/moodle2/temp/backup/c152ab51401407cda1745379b5f48577.log

Stack trace:

• line 46 of /backup/util/loggers/file_logger.class.php:      base_logger_exception thrown
• line 65 of /backup/util/factories/backup_factory.class.php: call to      file_logger->__construct()
• line 109 of /backup/controller/backup_controller.class.php: call to      backup_factory::get_logger_chain()
• line 84 of /backup/backup.php: call to      backup_controller->__construct()

Also  I have had a marked increase of Automated backup status error messages. I can't think of anything that has changed.

Thanks for any help.

Jim