BPM: Default Pathway and End Event


I'm hoping someone can assist with a Process Definition that is throwing me an Issue because I have no Default path set.

Goal of the process: 

A Portal Case is created and according to the "Product Category" the Customer used to create the case, an email is sent to the appropriate team letting them know the Case was created. 

Start Event: New Records only, where Source = Portal

I'm also confused as to why I need to set a default path (this is the issue that appears), as well as when to use the Do Nothing and Terminate features for the End Event. I don't understand all the implications to fully grasp how they're to be applied for different scenarios. 

I'll post the process here (or try to); we are hosted on Sugar with Enterprise Sell / Serve (some customizations with Serve and the Customer Portal).

Any insight and / or advice would be greatly appreciated!