A common question is parsing dates in .NET, especially British formats.
Couple of quick solutions are to add an entry to your web.config:
<globalization culture="en-GB" requestEncoding="utf-8" responseEncoding="utf-8" />
Or parse in code:
using System.Globalization;
...
string stringDate = "17/06/2005";
IFormatProvider culture = new CultureInfo("en-gb", false);
DateTime dateTimeDate = DateTime.Parse(stringDate, culture);