数据类型转换错误

如何创建表使用VB6的application.I tabledefs方法已成功地编写代码，但它在执行打印"数据类型转换错误"我有什么: -

Private Sub createDB(dbname As String)

    Dim db As Database

    Dim td As TableDef

    Dim fld As Field

    Set db = DBEngine(0).CreateDatabase(dbname, dbLangGeneral)

    Set td = db.CreateTableDef("Students_Info")

    With td

       Set fld = .CreateField("Rollno", dbNumber, 3)

         fld.AllowZeroLength = False

         fld.Required = True

         .Fields.Append fld

       

       Set fld = .CreateField("FirstName", dbText, 15)

         fld.AllowZeroLength = False

         fld.Required = True

         .Fields.Append fld

         

       Set fld = .CreateField("LastName", dbText, 15)

         fld.AllowZeroLength = False

         fld.Required = True

         .Fields.Append fld

         

       Set fld = .CreateField("DOB", dbDate)

         fld.AllowZeroLength = False

         fld.Required = True

         .Fields.Append fld

       

       Set fld = .CreateField("Class", dbText, 6)

         .Fields.Append fld

         

       Set fld = .CreateField("Subjects", dbText, 6)

         .Fields.Append fld

         

       Set fld = .CreateField("Mobile", dbLong, 10)

         fld.AllowZeroLength = False

         fld.Required = True

         .Fields.Append fld

         

       Set fld = .CreateField("Father's_name", dbText, 30)

          fld.AllowZeroLength = False

          fld.Required = True

          .Fields.Append fld

          

       Set fld = .CreateField("Mother's_Name", dbText, 30)

          fld.AllowZeroLength = False

          fld.Required = True

          .Fields.Append fld

          

       Set fld = .CreateField("Address", dbText, 60)

          fld.AllowZeroLength = False

          fld.Required = True

          .Fields.Append fld

          

       Set fld = .CreateField("E_Mail", dbText, 30)

          .Fields.Append fld

    End With

    db.TableDefs.Append td

 

End Sub