VS 2008 Invalid attempt to call metadata when reader is closed

I get this error " INVALID ATTEMPT TO CALL METADATA WHEN READER IS CLOSED " when i run my program.
The error comes in dr1=cmd2.executereader ( line 113). Plz help me to solve this error.

Below is my coding.

Private Sub cmbstudentid_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmbstudentid.SelectedIndexChanged
Try
Call connection()
sqlstr = "select _Name,_course_enro from Admission__details where _Eno like '%" & cmbstudentid.SelectedItem & "'"
cmd = New SqlCommand(sqlstr, con)
dr = cmd.ExecuteReader
While dr.Read
Me.txtname.Text = dr(0)
Me.txtcourseenrolled.Text = dr(1)
End While
dr.Close()
con.Close()
Call connection()
sqlstr2 = "select Cfees from Course_details where Cname like '%" & txtcourseenrolled.Text & "'"
Dim cmd2 = New SqlCommand(sqlstr2, con)
dr1 = cmd2.ExecuteReader
If dr1.HasRows = True Then
While dr1.Read
Me.txtcoursefees.Text = dr(0)
End While
End If
dr1.Close()
Catch ex As Exception
MsgBox(ex.Message)
End Try
con.Close()
End Sub