How to Identify the 'target' layer when "command X not available" appears when running an action?

Can you provide a screenshot illustrating your problem (text of error, expanded action and layers panel)?

As far as I understand, we are talking about actions. Disable the "button mode" mode if it is enabled and you will be able to see which command the action stopped on. In most cases, name of the layer that it expects written in command:

The fact that the action cannot find the correct layer may be due to a) the wrong structure of your document b) an error in the action itself c) the action may refer to layer names written in another language. If you do not have any additional information from the author of the action, then in cases a) and b) you will have to sequentially execute the action one step at a time to understand its logic, find and fix the error. In case c) it is quite easy to understand which layer the action needs and you just need to rewrite the command.