Internal Connection Fatal Error.

Hi all,I don’t know what happened to this function which was working OK for a few month and today it doesn’t work.In debug mode I kip getting “InvalidOperationaException was unhandled by user code”On this line:dtrResults = cmdSelect.ExecuteReader()Same behaviour on developping PCI cant find anithing that would create that problem. Function GetUserInfo(ByVal myUsr As String, ByVal strRequest As String) As String
Dim strConString As String
Dim conUsers As SqlConnection
Dim cmdSelect As SqlCommand

strConString = ConfigurationSettings.AppSettings("conString2")
conUsers = New SqlConnection(strConString)
Dim dtrResults As SqlDataReader
Dim intField As Integer
Dim usr As String
usr = "select " & strRequest & " user_ID from userlist where ul_user='"
usr &= myUsr & "'"
conUsers.Open()
cmdSelect = New SqlCommand(usr, conUsers)
dtrResults = cmdSelect.ExecuteReader()
While dtrResults.Read()
For intField = 0 To dtrResults.FieldCount - 1
GetUserInfo = dtrResults(intField).ToString()
Next
End While
conUsers.Close()
dtrResults.Close()
Return GetUserInfo
End Function   Any Help will highly appriciated.Alex.