Aeson exception: Error in $: Missing required field, either ByronGenesisFile or GenesisFile

Hi All
please does anyone know what this error means ?

It is very vague ?

Aeson exception:
Error in $: Missing required field, either ByronGenesisFile or GenesisFile

I have an Ubuntu VM running on VirtualBox, folowed the step by step guid but am unable to start the node.
I have tried hard coding the Path to the config files, nohiing seems to work.

thanks