You do not say what kind of error.
I assume that getreminders is null because your query gave no results.
You cannot access the Count property when getreminders is null.
You will get a null reference exception.
Use a debugger and see yourself.
OK. The red line is in your IDE.
Of course an IQueriable does not have a Count property.
You should convert it then to a list.
var getreminders = (from DB_A448D1_ilgswork in doAction.uni_projects
where DB_A448D1_ilgswork.DueBy == DateTime.Today.ToLongDateString()
select DB_A448D1_ilgswork).ToList();