Undefined variable: files

Getting below error when Amazon S3 bucket is mis-configured as destination

Notice: Undefined variable: files in backup_migrate_schedule->remove_expired_backups() (line 388 of  backup_migrate/includes/schedules.inc).

And S3 bucket throws User warning: S3::getBucket(): [RequestTimeTooSkewed] The difference between the request time and the current time is too large. in S3::__triggerError() (line 222 of /libraries/s3-php5-curl/S3.php).