This indicates that 3DMark 11 could not start up DirectX 11 graphics mode.

Verify that you actually have a DirectX 11 card. If not, 3DMark 11 will not run on your system.

Verify that you have latest DirectX libraries installed. If unsure, download and install the DirectX Web Installer.

Verify that you have latest video drivers for your card installed. If needed, completely uninstall your current drivers, reboot and then install latest drivers. Note that you may have to use third party driver cleaner utility to rectify the issue as that is the only way to remove any corrupted driver parts or registry entries.

Check your DXDiag (type "DXDiag" in start menu search box and run Microsoft DirectX Diagnostics) and check under Display (or Display 1) tab for "DDI Version: 11". If you see 10.1 (or lower) here and you have DirectX 11 hardware, you may have issues with your video drivers - a complete uninstallation and reinstallation of video drivers is recommended.