Custom error message for exceptions

This is the situation:

I want to throw an MException with a custom message, lets say:

            if(0 == this.Model.NumInputs)
                err = MException('jku.methods:InvalidModel', 'Invalid Tree. The prune of the tree gives an empty tree!');
                throw(err);
            end

How can I define that message identifier 'jku.methods:InvalidModel' ??? I am getting the error

??? Error using ==> MException IDENTIFIER input must be a valid MATLAB message identifier. For more information, search for "message identifier" in the MATLAB Help.

Thanks !!

Answer 1

[Walter Roberson]

The part before the ':' cannot contain a period.

[Kaustubha Govind]

Also, for more information: http://www.mathworks.com/help/releases/R2011b/techdoc/matlab_prog/bq9l448-1.html#bq9tdlq-1