Error using prctile because eml_is_const is not found

dear all,

I am using Matlab 2013b. I used prctile function. Yesterday, there is no problem at all but today, I got this error message

Undefined function 'eml_is_const' for input arguments of type 'double'.

Error in prctile (line 25) if eml_is_const(size(x)) && isequal(size(x),[0,0])

I tried to find by typing 'which eml_is_const' at Matlab prompt and the result is 'eml_is_const not found'

I restore the default path in the Matlab but the result is the same.

How to solve this problem?

Thank you

regards Hany