Error calculating with parameter 'Value' in simulink

In website "http://www.mathworks.com/matlabcentral/answers/92888-how-do-i-run-a-model-in-simulink-from-my-matlab-function-where-my-simulink-parameters-are-defined-in", there is a good answer "options = simset('SrcWorkspace','current'); sim('modelname',[],options)".

In my simulink model, a similar problem appears.

The simulink model contains a variable mask parameter "C". when I linearize a simulink model in M file, there is a error "Undefined function or variable 'C'". However, the above fuctions "options = simset('SrcWorkspace','current'); sim('modelname',[],options)" are not properly here.

Could you give any suggestion for me to solve this problem. Thank you!