مشكلة في الdataset تحتوي على 3 جداول

لدي المشكلة التالية:

استعمل vb.net2003 و sql server2000 و استعمل الوضع المنفصل في الاتصال..

و لدي 3 جداول, وضعت كلا منهم في SqlDataAdapter لوحده , ثم جمعتهم في DataSet واحده لعرض البيانات في data grid واحده , المشكلة تظهر عند عمل بحث, حيث يعرض النتائج لفترة , ثم تظهر لي المسج التالية:

there is already an open DataReader associated with this connection which must be closed first.

, وعند عمل تعديل يظهر المسج:

invalid attemp to read when data is in percent

مع العلم اني لم أغير تصميم الجداول أو خصائص الحقول, وقد حذفت ال SqlDataAdapter والDataSet و ا SqlConnectionو عملتهم مرة اخرى و لكن نفس النتيجة يعمل لفترة ثم تظهر المسج, وكذلك كود البحث و التعديل يعمل في شاشة أخرى مكونه من جدولين بشكل صحيح تماما...أما في هذه الشاشة لا..

أعتقد انا أن المشكلة تتعلق بكون الdatagrid تحتوي على 3 جداول ولكن لا اعرف ما الحل ؟

وهذا هو كود البحث:

 Try
			If Me.cbInstructorID1.Checked = False And Me.cbInstructorName1.Checked = False And Me.cbQualifications1.Checked = False Then
				MsgBox("لم يتم اختيار مفتاح للبحث")
			Else



				Dim SearchInstructorID As Integer
				Dim SearchInstructorName, SearchQualification As String
				SQLstatment = "select * from Instructor "



				If Me.cbInstructorID1.Checked = True Then
					If Val(Me.txtSearchInstructorID1.Text) >= 0 Then
						If SQLstatment = "select * from Instructor " Then
							SQLstatment = SQLstatment + " where Instructor_ID=" + Str(Val(Me.txtSearchInstructorID1.Text))

						Else
							SQLstatment = SQLstatment + " and Instructor_ID=" + Str(Val(Me.txtSearchInstructorID1.Text))

						End If
					End If
				End If


				If Me.cbInstructorName1.Checked = True Then
					If Me.txtSearchInstructorName1.Text <> "" Then
						If SQLstatment = "select * from Instructor " Then
							SQLstatment = SQLstatment + "where Instructor_Name like N'%" + Me.txtSearchInstructorName1.Text + "%'"

						Else
							SQLstatment = SQLstatment + "and Instructor_Name like N'%" + Me.txtSearchInstructorName1.Text + "%'"
						End If
					End If
				End If


				If Me.cbQualifications1.Checked = True Then
					If Me.txtSearchQualifications1.Text <> "" Then
						If SQLstatment = "select * from Instructor " Then
							SQLstatment = SQLstatment + "where Qualifications like N'%" + Me.txtSearchQualifications1.Text + "%'"
						Else
							SQLstatment = SQLstatment + "and Qualifications like N'%" + Me.txtSearchQualifications1.Text + "%'"
						End If
					End If
				End If



				'MsgBox("final SQL statement is :  " + SQLstatment)

				Dim cmdSearch As New SqlCommand
				cmdSearch.CommandText = SQLstatment
				cmdSearch.Connection = MyConn
				MyConn.ConnectionString = "workstation id=local;packet size=4096;integrated security=SSPI;data source='';persist security info=False;initial catalog=TCCNR"

				If MyConn.State = ConnectionState.Closed Then
					MyConn.Open()
				End If

				Dim drSearch As SqlDataReader = cmdSearch.ExecuteReader



				drSearch.Read()
				If drSearch.HasRows = False Then
					MsgBox("لا يوجد سجلات مطابقة !!")
					Me.btnModify1.Enabled = False
					Me.btnEraseDBFields.Enabled = False


				Else
					'---------new---------------------------------------

					Dim cmdMySearch As New SqlCommand
					cmdMySearch.CommandText = SQLstatment
					cmdMySearch.Connection = Me.SqlConnection1

					Dim cmdViewWorkPlace As New SqlCommand
					Dim WorkPlace_SQL_Statement As String
					WorkPlace_SQL_Statement = "select * from Work_Place;"
					cmdViewWorkPlace.CommandText = WorkPlace_SQL_Statement
					cmdViewWorkPlace.Connection = Me.SqlConnection1

					Dim cmdViewNationality As New SqlCommand
					Dim Nationality_SQL_Statement As String
					Nationality_SQL_Statement = "select * from Nationality;"
					cmdViewNationality.CommandText = Nationality_SQL_Statement
					cmdViewNationality.Connection = Me.SqlConnection1



					If SqlConnection1.State = ConnectionState.Closed Then
						SqlConnection1.Open()
					End If

					Me.SqlDataAdapter1.SelectCommand = cmdMySearch
					Me.SqlDataAdapter2.SelectCommand = cmdViewWorkPlace
					Me.SqlDataAdapter3.SelectCommand = cmdViewNationality


					Me.DS_Instructors1.Clear()

					Me.SqlDataAdapter1.Fill(Me.DS_Instructors1)
					Me.SqlDataAdapter2.Fill(Me.DS_Instructors1)
					Me.SqlDataAdapter3.Fill(Me.DS_Instructors1)

					SqlConnection1.Close()

					Me.NDG_Search_Instructor.Enabled = True
					Me.btnModify1.Enabled = True
					Me.btnEraseDBFields.Enabled = True

					Me.NDG_Search_Instructor.Expand(-1)
					'------------------------------------------------------------------
					Me.txtSearchInstructorID1.Text = Val(drSearch.Item("Instructor_ID"))
					Me.txtSearchInstructorName1.Text = drSearch.Item("Instructor_Name")
					Me.txtSearchQualifications1.Text = drSearch.Item("Qualifications")
					Me.btnModify1.Enabled = True

				End If

				drSearch.Close()
				MyConn.Close()

			End If



		Catch ex1 As SqlException
			MsgBox(ex1.Message)
			MyConn.Close()
		Catch ex2 As Exception
			MsgBox(ex2.Message)
			MyConn.Close()

		End Try

وكود التعديل:

		Me.SqlDataAdapter1.Update(Me.DS_Instructors1)

		Me.SBInstructors.Text = "تم حفظ البيانات بنجاح "
		'---------------------------------------------------------------
		Dim db As New SqlCommandBuilder(da)

		da.UpdateCommand = db.GetUpdateCommand
		da.DeleteCommand = db.GetDeleteCommand
		da.InsertCommand = db.GetInsertCommand


		da.Update(ds, "Instructor")

أرجو ممن يعرف الحل أن يساعدني , وله مني خالص الدعاء...