HELP!..... What is mean " A constraint has been violated."

I am trying everything but it is still going on!.... Almost I changed all of bloks values and Base->Follow directions but did not work!.... İn short ı could not solve this problem!...

Diagnostic View:

Error originates in Mechanical block nms_model_SON_2_hat_kalcaya_bagli/Body Mechanics Layer/Left Thigh Sensor Sheet
Subsystem/Left Thigh
Sensor Sheet/Inner Thigh
Shift Joint. A constraint has been violated. Check constraint solver type and tolerances in the Machine Environment block and Simulink solver and tolerances in Configuration Parameters. Check for kinematic singularities.

Pleas Help me URGENTLY!... :(((((

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency