DataSource Controls :: C# VS 2008 / SQL Server 2005 Express Website Error "Conversion Failed When Converting Datetime From Character String"

I am developing a C# VS 2008 / SQL Server 2005 Express website application. I have tried some of the fixes for this problem but my call stack differs from others. And these fixes did not fix my problem. What steps can I take to troubleshoot this?

System.Data.SqlClient.SqlException was caught
Message="Conversion failed when converting datetime from character string."
Source=".Net SqlClient Data Provider"
ErrorCode=-2146232060
LineNumber=10
Number=241
Procedure="AppendDataCT"
Server="\\.\pipe\772EF469-84F1-43\tsql\query"
State=1
StackTrace:
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
at ADONET_namespace.ADONET_methods.AppendDataCT(DataTable dt, Dictionary`2 dic) in c:Documents and SettingsAdminMy DocumentsVisual Studio 2008WebSitesJerryApp_CodeADONET methods.cs:line 102
And here is the related code. When I debugged this code, "dic" only looped through the 3 column names, but did not look into row values which are stored in "dt", the Data Table.
public static string AppendDataCT(DataTable dt, Dictionary<string, string> dic)
{
if (dic.Count != 3)
throw new ArgumentOutOfRangeException("dic can only have 3 parameters");
string connString = ConfigurationManager.ConnectionStrings["AW3_string"].ConnectionString;
string errorMsg;
try
{
using (SqlConnection conn2 = new SqlConnection(connString))
{
using (SqlCommand cmd = conn2.CreateCommand())
{
cmd.CommandText = "dbo.AppendDataCT";
cmd.CommandType = CommandType.StoredProcedure;
cmd.Connection = conn2;
foreach (string s in dic.Keys)
{
SqlParameter p = cmd.Parameters.AddWithValue(s, dic[s]);
p.SqlDbType = SqlDbType.VarChar;
}
conn2.Open();
cmd.ExecuteNonQuery();
conn2.Close();
errorMsg = "The Person.ContactType table was successfully updated!";
}
}
}