Hi @Eric_Morera1, welcome to the community and sorry for the trouble.
The error message here hints towards the cause of the problem: Your expression {{ $('Webhook').item.json.body[0].propertyValue }} is looking up data from a node before your Code node. It will do this through an approach called item linking (aka paired items) documented here. This will not work out of the box with the Code node as n8n cannot automatically make a connection between your current item and items from before your Code node.
From looking at your workflow you have two main options here I think:
Provide the required data in your Code nodes. This is documented here.
Alternatively pick an expression not relying on item linking functionality. Seeing a Webhook node typically returns only one item you could go with {{ $('Webhook').first().json.body[0].propertyValue }} for example