Error messages when file path specification is wrong

[alexander-held]

Is your feature request related to a problem? Please describe.
I was testing running over a local file with a LocalCluster and messed up the file path. dataset_tools.preprocess then crashes and reports

IndexError: cannot slice EmptyArray (of length 0) with ['file', 'object_path', 'steps', 'uuid']: not an array of records

This error occurred while attempting to slice

    <Array [None] type='1 * ?unknown'>

with

    ['file', 'object_path', 'steps', 'uuid']

Describe the solution you'd like
I think it would be helpful to catch this issue explicitly to have a more informative error message like "no file found at this path".

Describe alternatives you've considered
No change, so leave it to user to discover underlying problem.

Additional context
n/a

[jennetd]

I just encountered the same issue and agree a more descriptive error would be much better