Encountering similar errors. worker.error log is below
erpnext@ip-172-31-1-158:~/frappe-bench/logs$ tail worker.error.log
return callback(*args, **kwargs)
File "/home/erpnext/frappe-bench/apps/frappe/frappe/commands/scheduler.py", line 157, in start_worker
start_worker(queue)
File "/home/erpnext/frappe-bench/apps/frappe/frappe/utils/background_jobs.py", line 102, in start_worker
Worker(queues, name=get_worker_name(queue)).work()
File "/home/erpnext/frappe-bench/env/local/lib/python2.7/site-packages/rq/worker.py", line 135, in __init__
self.validate_queues()
File "/home/erpnext/frappe-bench/env/local/lib/python2.7/site-packages/rq/worker.py", line 179, in validate_queues
raise TypeError('{0} is not of type {1} or text type'.format(queue, self.queue_class))
TypeError: short is not of type <class 'rq.queue.Queue'> or text type
erpnext@ip-172-31-1-158:~/frappe-bench/logs$