MARSS numbers are 13 digit numbers. The new update of SpEd Forms requires that the MARSS number be exactly 13 digits with no spaces, alphabet characters or special characters. Special characters are things like underscores (_), asterisks (*) or tildes(~). Some reports will not run if the MARSS number does not meet the standard.
If you have a non-standard MARSS number for a student, please change it. Here is a short movie showing how to change it.