A company code is necessary even without the Multi-Comapnies module, because the Intranet WebApp needs it for its URL. Check whether a company code has been entered and add it if necessary.
Go to the Administration Tab and select Settings > Company or Administration > Company settings > Company and make sure that company Codes have been entered.
Use the code later in the URL for the WebApp, even for companies without multi-companies. Example: http://{Servername}/WebApp_Intranet_V2/client.html?company=GG