Sharepoint:Cannot insert item when referencing a control from code behind

Question

Hi all

I have a custom NewItem.aspx form made as a new asp from the existing one.

I modified a form field and replaced it with an ASP.NET TextBox as in this

the text box is like this

<asp:TextBox runat="server" id="txtDesc" __designer:bind="{ddwrt:DataBind('i','txtDesc','Text','TextChanged','ID',ddwrt:EscapeDelims(string(@ID)),'@General_x0020_Features')}"></asp:TextBox>

when I insert a new item it works fine.

I need to put a default value in this text box that is obtained from another database,

the problem is whenever I reference the text box from the code behind. the Item never gets inserted in the list.

is there any workaround for this ?

thanks.