generate ID

Question

i have made 7 tables and i have mentioned separate id in all the tables. in my application i have made one connectionclass to contain the connection string and the definitions. here i am posting the link of my tables and one of my form. i want to generate the ID. i have used a definition and the coding to generate it but its not working. plz help........ http://www.mediafire.com/?sharekey=1f652cd338abc55207258ee67c679e4abaa8ae67e4e2175f5be6ba49b5870170