The drive-time tool is dependant on the streets network in order to calculate drive times or drive distances.
From the Business Analyst drop-down menu, select Preferences. Select the Datasets tab. Near the bottom of the tab, click the windows browse button next to the Streets Network drop-down button, browse to ...Program Files\ArcGIS\Business Analyst\Data\Tele Atlas Street Data\trans, and select the streets network. A windows error may have occurred to break this link with the streets network. Following these steps will reestablish the link and allow you to run drive times and drive distances.