Datetime control show Let us know why you need access to this site.

DateTimeControl field uses the iframe calender page to render the actual calender. The location of iframe.aspx is C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS

The problem appeared to be with managed paths in the site collections, the Users with "Contribute access" were accessing the following path:

http://myserver/_layouts/iframe.aspx (Path to Root site collection where user doesn't have access)

The solution:

using  C#:
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<SharePoint:DateTimeControl ID="dtcStartDate" runat="server" DateOnly="true"/>

dtcStartDate.DatePickerFrameUrl = SPContext.Current.Web.Url + "/_layouts/iframe.aspx"; 

OR 

<SharePoint:DateTimeControl ID="dtcStartDate" runat="server" DateOnly="true" DatePickerFrameUrl="../../_layouts/iframe.aspx"/>



In sharepoint views:
 --------------------------
<SharePoint:DateTimeControl runat=server  id="dtctrlStartDate" DateOnly="true" DatePickerFrameUrl="../../_layouts/iframe.aspx"/>