If you search the streetmap folder, can you locate a streets.rs file? That is what you need to navigate to in ArcCatalog and it will show up as streets with a network icon that you can add to ArcMap. You should also see a streets.rsx folder that contains the network information. If you cannot find that file then you may not have the product properly installed.
Also make sure that product is licensed on the computer you are trying to use it in. If you are not sure you can use the ArcGIS Adminstrator to see your data licenses.