Why does the mdlElmdscr_new function not operate?

Hi,

your question doesn't contain any valuable information, which can help to answer or to propose a solution.

Without knowing what exception happens and what code do you use, don't expect anybody will be able to help you.

Until the information will be known, the only answer is "It's becuse there is a bug in your code."

With regards,

  Jan

Unknown said:

I'd like to know what are the reasons that prevent the good execution of this function

We can't see your code, so we can't tell you why it doesn't work.  Post a code snippet.