This error indicates that some other application or background task interrupted 3DMark 11 by attempting to draw something on the screen while the benchmark was running.
To solve the issue, please close background applications and desktop widgets. This includes 3D tweaking utilities, temperature/fan monitoring utilities, VPN and remote desktop applications, and any other applications that may draw a pop-up window or notification on top of a full screen application.
As a general rule, you should close all unneeded background applications before benchmarking to maximize the available system resources. Background applications can negatively influence your benchmark score.