windows application - updating database

Question

Hi there ! When I'm trying to update an existing row in a table, i recieve the following error : An unhandled exception of type 'System.Data.ConstraintException' occurred in system.data.dll Additional information: Column 'StudentID, CourseID, Type' is constrained to be unique. Value '1234567, course 06, master' is already present. I use sql server 2000. Does anyone Knows how to fix the problem ? moreno