Need help with Popup Calender, won't close and update Textfield

Hi,
I've been looking every for a simple Popup calender solution for my VWD site. I came across this bit of code and I got the popup with the calender displayed but the calender doesn't close and populate my text box field on the calling page. Here is the code to pass the value and close the calendar window:

Dim strjscript As String = "<script language=""javascript"">"
strjscript &= "window.opener." & _
HttpContext.Current.Request.QueryString("formname") & ".value = '" & _Calendar1.SelectedDate & "';window.close();"
Literal1.Text = strjscript

which looks like this when built as a string:
"<script language="javascript">window.opener.frmCalendar.txtDate.value = '25/11/2005';window.close();"

So, essentially this is suppose to put the date "25/11/2005" in the textbox:  txtDate of the window that called this popup and close the Calendar picker window. When I run this however, nothing happens. If I change the script to:

"<script language="javascript">window.close();"

It closes the window, so with some deduction.... LOL there must be something wrong with window.opener.frmCalendar.txtDate.value = '25/11/2005'; One other note: this txtDate field is located within a MasterPage. I read somewhere that a person had the same problem and when he removed the page from being a part of the masterpage everything worked. Any help would be greatly appreciated. Thanks