We have solved the issue with accessing the database listing, altough the display may not be optimal, yet - however, there is still a little error in your code. You store an object by using dbStore(), but try to retrieve an array via dbGet().
Either use dbSet() and dbGet()
Or use dbStore() and dbRetrieve()
The second option will allow you to store single values, an associative array or even arrays within arrays.
Please let us know, if you still encounter an error 500 - and if so, please tell us the time. Thank you.