Unable to create Custom Work Item Type

you have not set up the editors for your presentation of the work item. Looks like you are trying to create a work item from the web you need to mape the lightweight work Item editor in order to see the fields etc.

you can do that no problem you need to go through the process. Create the fields you want and then create the editor presentation. You will need to add to it this might be something more than just updates to the forum question. Have you looked at the documentation for creating the editor presentation? If not that's a good place to start. Not sure where you are located if you want a little guidance I can give you some pointers. easier with email or a phone call.