and on line 110 you are trying to create an instance of SqlCommandBuilder
cb = new System.Data.SqlClient.SqlCommandBuilder(da1);
An sql compact db is not the same as another type of db. You are trying to instansiate a SqlCommandBuilder object whilst passing it a SqlCeDataAdapter. You cannot do this. You need to pass a SqlCeDataAdapter to a SqlCeCommandBuilder.
System.Data.SqlServerCe.SqlCeCommandBuilder cb = new SqlCeCommandBuilder(da1);