Error in page http://www.mywebsite.com/item_details.aspx?AdId=899'/**/AND/**/1=2--

Hi there,
I am getting this error on my website and am a bit concerned if it is related to security of my site. Can anyone please help to shed some light into it? My thanks in advance.
 
Error in page http://www.mywebsite.com/item_details.aspx?AdId=899'/**/AND/**/1=2--
Message
Input string was not in a correct format.
StackTrace
at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) at System.String.System.IConvertible.ToInt32(IFormatProvider provider) at System.Convert.ChangeType(Object value, TypeCode typeCode, IFormatProvider provider) at System.Web.UI.WebControls.Parameter.GetValue(Object value, ...